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@isXander isXander commented Sep 2, 2021

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jelly commented Sep 2, 2021

This repository does not accept pull requests, fill a bug on the bugtracker if this was officially accepted upstream and can be backported.

@jelly jelly closed this Sep 2, 2021
heftig pushed a commit that referenced this pull request Sep 8, 2021
Recent changes exposed a bug where specifically-timed requests to the
path manager netlink API could trigger a divide-by-zero in
__tcp_select_window(), as syzkaller does:

divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 0 PID: 9667 Comm: syz-executor.0 Not tainted 5.14.0-rc6+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:__tcp_select_window+0x509/0xa60 net/ipv4/tcp_output.c:3016
Code: 44 89 ff e8 c9 29 e9 fd 45 39 e7 0f 8d 20 ff ff ff e8 db 28 e9 fd 44 89 e3 e9 13 ff ff ff e8 ce 28 e9 fd 44 89 e0 44 89 e3 99 <f7> 7c 24 04 29 d3 e9 fc fe ff ff e8 b7 28 e9 fd 44 89 f1 48 89 ea
RSP: 0018:ffff888031ccf020 EFLAGS: 00010216
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000
RDX: 0000000000000000 RSI: ffff88811532c080 RDI: 0000000000000002
RBP: 0000000000000000 R08: ffffffff835807c2 R09: 0000000000000000
R10: 0000000000000004 R11: ffffed1020b92441 R12: 0000000000000000
R13: 1ffff11006399e08 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fa4c8344700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f424000 CR3: 000000003e4e2003 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
 tcp_select_window net/ipv4/tcp_output.c:264 [inline]
 __tcp_transmit_skb+0xc00/0x37a0 net/ipv4/tcp_output.c:1351
 __tcp_send_ack.part.0+0x3ec/0x760 net/ipv4/tcp_output.c:3972
 __tcp_send_ack net/ipv4/tcp_output.c:3978 [inline]
 tcp_send_ack+0x7d/0xa0 net/ipv4/tcp_output.c:3978
 mptcp_pm_nl_addr_send_ack+0x1ab/0x380 net/mptcp/pm_netlink.c:654
 mptcp_pm_remove_addr+0x161/0x200 net/mptcp/pm.c:58
 mptcp_nl_remove_id_zero_address+0x197/0x460 net/mptcp/pm_netlink.c:1328
 mptcp_nl_cmd_del_addr+0x98b/0xd40 net/mptcp/pm_netlink.c:1359
 genl_family_rcv_msg_doit.isra.0+0x225/0x340 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x341/0x5b0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x148/0x430 net/netlink/af_netlink.c:2504
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x537/0x750 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x846/0xd80 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0x14e/0x190 net/socket.c:724
 ____sys_sendmsg+0x709/0x870 net/socket.c:2403
 ___sys_sendmsg+0xff/0x170 net/socket.c:2457
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

mptcp_pm_nl_addr_send_ack() was attempting to send a TCP ACK on the
first subflow in the MPTCP socket's connection list without validating
that the subflow was in a suitable connection state. To address this,
always validate subflow state when sending extra ACKs on subflows
for address advertisement or subflow priority change.

Fixes: 84dfe36 ("mptcp: send out dedicated ADD_ADDR packet")
Closes: multipath-tcp/mptcp_net-next#229
Co-developed-by: Paolo Abeni <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Acked-by: Geliang Tang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
heftig pushed a commit that referenced this pull request Sep 8, 2021
Patch series "kasan: test: avoid crashing the kernel with HW_TAGS", v2.

KASAN tests do out-of-bounds and use-after-free accesses.  Running the
tests works fine for the GENERIC mode, as it uses qurantine and redzones.
But the HW_TAGS mode uses neither, and running the tests might crash the
kernel.

Rework the tests to avoid corrupting kernel memory.

This patch (of 8):

Rework kmalloc_oob_right() to do these bad access checks:

1. An unaligned access one byte past the requested kmalloc size
   (can only be detected by KASAN_GENERIC).
2. An aligned access into the first out-of-bounds granule that falls
   within the aligned kmalloc object.
3. Out-of-bounds access past the aligned kmalloc object.

Test #3 deliberately uses a read access to avoid corrupting memory.
Otherwise, this test might lead to crashes with the HW_TAGS mode, as it
neither uses quarantine nor redzones.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/474aa8b7b538c6737a4c6d0090350af2e1776bef.1628779805.git.andreyknvl@gmail.com
Signed-off-by: Andrey Konovalov <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
heftig pushed a commit that referenced this pull request Sep 8, 2021
Patch series "mm/memory_hotplug: "auto-movable" online policy and memory groups", v3.

I. Goal

The goal of this series is improving in-kernel auto-online support.  It
tackles the fundamental problems that:

 1) We can create zone imbalances when onlining all memory blindly to
    ZONE_MOVABLE, in the worst case crashing the system. We have to know
    upfront how much memory we are going to hotplug such that we can
    safely enable auto-onlining of all hotplugged memory to ZONE_MOVABLE
    via "online_movable". This is far from practical and only applicable in
    limited setups -- like inside VMs under the RHV/oVirt hypervisor which
    will never hotplug more than 3 times the boot memory (and the
    limitation is only in place due to the Linux limitation).

 2) We see more setups that implement dynamic VM resizing, hot(un)plugging
    memory to resize VM memory. In these setups, we might hotplug a lot of
    memory, but it might happen in various small steps in both directions
    (e.g., 2 GiB -> 8 GiB -> 4 GiB -> 16 GiB ...). virtio-mem is the
    primary driver of this upstream right now, performing such dynamic
    resizing NUMA-aware via multiple virtio-mem devices.

    Onlining all hotplugged memory to ZONE_NORMAL means we basically have
    no hotunplug guarantees. Onlining all to ZONE_MOVABLE means we can
    easily run into zone imbalances when growing a VM. We want a mixture,
    and we want as much memory as reasonable/configured in ZONE_MOVABLE.
    Details regarding zone imbalances can be found at [1].

 3) Memory devices consist of 1..X memory block devices, however, the
    kernel doesn't really track the relationship. Consequently, also user
    space has no idea. We want to make per-device decisions.

    As one example, for memory hotunplug it doesn't make sense to use a
    mixture of zones within a single DIMM: we want all MOVABLE if
    possible, otherwise all !MOVABLE, because any !MOVABLE part will easily
    block the whole DIMM from getting hotunplugged.

    As another example, virtio-mem operates on individual units that span
    1..X memory blocks. Similar to a DIMM, we want a unit to either be all
    MOVABLE or !MOVABLE. A "unit" can be thought of like a DIMM, however,
    all units of a virtio-mem device logically belong together and are
    managed (added/removed) by a single driver. We want as much memory of
    a virtio-mem device to be MOVABLE as possible.

 4) We want memory onlining to be done right from the kernel while adding
    memory, not triggered by user space via udev rules; for example, this
    is reqired for fast memory hotplug for drivers that add individual
    memory blocks, like virito-mem. We want a way to configure a policy in
    the kernel and avoid implementing advanced policies in user space.

The auto-onlining support we have in the kernel is not sufficient.  All we
have is a) online everything MOVABLE (online_movable) b) online everything
!MOVABLE (online_kernel) c) keep zones contiguous (online).  This series
allows configuring c) to mean instead "online movable if possible
according to the coniguration, driven by a maximum MOVABLE:KERNEL ratio"
-- a new onlining policy.

II. Approach

This series does 3 things:

 1) Introduces the "auto-movable" online policy that initially operates on
    individual memory blocks only. It uses a maximum MOVABLE:KERNEL ratio
    to make a decision whether a memory block will be onlined to
    ZONE_MOVABLE or not. However, in the basic form, hotplugged KERNEL
    memory does not allow for more MOVABLE memory (details in the
    patches). CMA memory is treated like MOVABLE memory.

 2) Introduces static (e.g., DIMM) and dynamic (e.g., virtio-mem) memory
    groups and uses group information to make decisions in the
    "auto-movable" online policy across memory blocks of a single memory
    device (modeled as memory group). More details can be found in patch
    #3 or in the DIMM example below.

 3) Maximizes ZONE_MOVABLE memory within dynamic memory groups, by
    allowing ZONE_NORMAL memory within a dynamic memory group to allow for
    more ZONE_MOVABLE memory within the same memory group. The target use
    case is dynamic VM resizing using virtio-mem. See the virtio-mem
    example below.

I remember that the basic idea of using a ratio to implement a policy in
the kernel was once mentioned by Vitaly Kuznetsov, but I might be wrong (I
lost the pointer to that discussion).

For me, the main use case is using it along with virtio-mem (and DIMMs /
ppc64 dlpar where necessary) for dynamic resizing of VMs, increasing the
amount of memory we can hotunplug reliably again if we might eventually
hotplug a lot of memory to a VM.

III. Target Usage

The target usage will be:

 1) Linux boots with "mhp_default_online_type=offline"

 2) User space (e.g., systemd unit) configures memory onlining (according
    to a config file and system properties), for example:
    * Setting memory_hotplug.online_policy=auto-movable
    * Setting memory_hotplug.auto_movable_ratio=301
    * Setting memory_hotplug.auto_movable_numa_aware=true

 3) User space enabled auto onlining via "echo online >
    /sys/devices/system/memory/auto_online_blocks"

 4) User space triggers manual onlining of all already-offline memory
    blocks (go over offline memory blocks and set them to "online")

IV. Example

For DIMMs, hotplugging 4 GiB DIMMs to a 4 GiB VM with a configured ratio of
301% results in the following layout:
	Memory block 0-15:    DMA32   (early)
	Memory block 32-47:   Normal  (early)
	Memory block 48-79:   Movable (DIMM 0)
	Memory block 80-111:  Movable (DIMM 1)
	Memory block 112-143: Movable (DIMM 2)
	Memory block 144-275: Normal  (DIMM 3)
	Memory block 176-207: Normal  (DIMM 4)
	... all Normal
	(-> hotplugged Normal memory does not allow for more Movable memory)

For virtio-mem, using a simple, single virtio-mem device with a 4 GiB VM
will result in the following layout:
	Memory block 0-15:    DMA32   (early)
	Memory block 32-47:   Normal  (early)
	Memory block 48-143:  Movable (virtio-mem, first 12 GiB)
	Memory block 144:     Normal  (virtio-mem, next 128 MiB)
	Memory block 145-147: Movable (virtio-mem, next 384 MiB)
	Memory block 148:     Normal  (virtio-mem, next 128 MiB)
	Memory block 149-151: Movable (virtio-mem, next 384 MiB)
	... Normal/Movable mixture as above
	(-> hotplugged Normal memory allows for more Movable memory within
	    the same device)

Which gives us maximum flexibility when dynamically growing/shrinking a
VM in smaller steps.

V. Doc Update

I'll update the memory-hotplug.rst documentation, once the overhaul [1] is
usptream. Until then, details can be found in patch #2.

VI. Future Work

 1) Use memory groups for ppc64 dlpar
 2) Being able to specify a portion of (early) kernel memory that will be
    excluded from the ratio. Like "128 MiB globally/per node" are excluded.

    This might be helpful when starting VMs with extremely small memory
    footprint (e.g., 128 MiB) and hotplugging memory later -- not wanting
    the first hotplugged units getting onlined to ZONE_MOVABLE. One
    alternative would be a trigger to not consider ZONE_DMA memory
    in the ratio. We'll have to see if this is really rrequired.
 3) Indicate to user space that MOVABLE might be a bad idea -- especially
    relevant when memory ballooning without support for balloon compaction
    is active.

This patch (of 9):

For implementing a new memory onlining policy, which determines when to
online memory blocks to ZONE_MOVABLE semi-automatically, we need the
number of present early (boot) pages -- present pages excluding hotplugged
pages.  Let's track these pages per zone.

Pass a page instead of the zone to adjust_present_page_count(), similar as
adjust_managed_page_count() and derive the zone from the page.

It's worth noting that a memory block to be offlined/onlined is either
completely "early" or "not early".  add_memory() and friends can only add
complete memory blocks and we only online/offline complete (individual)
memory blocks.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Marek Kedzierski <[email protected]>
Cc: Hui Zhu <[email protected]>
Cc: Pankaj Gupta <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
heftig pushed a commit that referenced this pull request Sep 8, 2021
When the refcount is decreased to 0, the resource reclamation branch is
entered.  Before CPU0 reaches the race point (1), CPU1 may obtain the
spinlock and traverse the rbtree to find 'root', see
nilfs_lookup_root().

Although CPU1 will call refcount_inc() to increase the refcount, it is
obviously too late.  CPU0 will release 'root' directly, CPU1 then
accesses 'root' and triggers UAF.

Use refcount_dec_and_lock() to ensure that both the operations of
decrease refcount to 0 and link deletion are lock protected eliminates
this risk.

	     CPU0                      CPU1
	nilfs_put_root():
		    <-------- (1)
				spin_lock(&nilfs->ns_cptree_lock);
				rb_erase(&root->rb_node, &nilfs->ns_cptree);
				spin_unlock(&nilfs->ns_cptree_lock);

	kfree(root);
		    <-------- use-after-free

  refcount_t: underflow; use-after-free.
  WARNING: CPU: 2 PID: 9476 at lib/refcount.c:28 \
  refcount_warn_saturate+0x1cf/0x210 lib/refcount.c:28
  Modules linked in:
  CPU: 2 PID: 9476 Comm: syz-executor.0 Not tainted 5.10.45-rc1+ #3
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
  RIP: 0010:refcount_warn_saturate+0x1cf/0x210 lib/refcount.c:28
  ... ...
  Call Trace:
     __refcount_sub_and_test include/linux/refcount.h:283 [inline]
     __refcount_dec_and_test include/linux/refcount.h:315 [inline]
     refcount_dec_and_test include/linux/refcount.h:333 [inline]
     nilfs_put_root+0xc1/0xd0 fs/nilfs2/the_nilfs.c:795
     nilfs_segctor_destroy fs/nilfs2/segment.c:2749 [inline]
     nilfs_detach_log_writer+0x3fa/0x570 fs/nilfs2/segment.c:2812
     nilfs_put_super+0x2f/0xf0 fs/nilfs2/super.c:467
     generic_shutdown_super+0xcd/0x1f0 fs/super.c:464
     kill_block_super+0x4a/0x90 fs/super.c:1446
     deactivate_locked_super+0x6a/0xb0 fs/super.c:335
     deactivate_super+0x85/0x90 fs/super.c:366
     cleanup_mnt+0x277/0x2e0 fs/namespace.c:1118
     __cleanup_mnt+0x15/0x20 fs/namespace.c:1125
     task_work_run+0x8e/0x110 kernel/task_work.c:151
     tracehook_notify_resume include/linux/tracehook.h:188 [inline]
     exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
     exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
     syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
     do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
     entry_SYSCALL_64_after_hwframe+0x44/0xa9

There is no reproduction program, and the above is only theoretical
analysis.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: ba65ae4 ("nilfs2: add checkpoint tree to nilfs object")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Zhen Lei <[email protected]>
Signed-off-by: Ryusuke Konishi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
heftig pushed a commit that referenced this pull request Sep 12, 2021
We update the ctime/mtime of a block device when we remove it so that
blkid knows the device changed.  However we do this by re-opening the
block device and calling filp_update_time.  This is more correct because
it'll call the inode->i_op->update_time if it exists, but the block dev
inodes do not do this.  Instead call generic_update_time() on the
bd_inode in order to avoid the blkdev_open path and get rid of the
following lockdep splat:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ torvalds#406 Not tainted
------------------------------------------------------
losetup/11596 is trying to acquire lock:
ffff939640d2f538 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0

but task is already holding lock:
ffff939655510c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       lo_open+0x28/0x60 [loop]
       blkdev_get_whole+0x25/0xf0
       blkdev_get_by_dev.part.0+0x168/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       do_sys_openat2+0x7b/0x130
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #3 (&disk->open_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       blkdev_get_by_dev.part.0+0x56/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       file_open_name+0xc7/0x170
       filp_open+0x2c/0x50
       btrfs_scratch_superblocks.part.0+0x10f/0x170
       btrfs_rm_device.cold+0xe8/0xed
       btrfs_ioctl+0x2a31/0x2e70
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #2 (sb_writers#12){.+.+}-{0:0}:
       lo_write_bvec+0xc2/0x240 [loop]
       loop_process_work+0x238/0xd00 [loop]
       process_one_work+0x26b/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
       process_one_work+0x245/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
       __lock_acquire+0x10ea/0x1d90
       lock_acquire+0xb5/0x2b0
       flush_workqueue+0x91/0x5e0
       drain_workqueue+0xa0/0x110
       destroy_workqueue+0x36/0x250
       __loop_clr_fd+0x9a/0x660 [loop]
       block_ioctl+0x3f/0x50
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_mutex);
                               lock(&disk->open_mutex);
                               lock(&lo->lo_mutex);
  lock((wq_completion)loop0);

 *** DEADLOCK ***

1 lock held by losetup/11596:
 #0: ffff939655510c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

stack backtrace:
CPU: 1 PID: 11596 Comm: losetup Not tainted 5.14.0-rc2+ torvalds#406
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
 dump_stack_lvl+0x57/0x72
 check_noncircular+0xcf/0xf0
 ? stack_trace_save+0x3b/0x50
 __lock_acquire+0x10ea/0x1d90
 lock_acquire+0xb5/0x2b0
 ? flush_workqueue+0x67/0x5e0
 ? lockdep_init_map_type+0x47/0x220
 flush_workqueue+0x91/0x5e0
 ? flush_workqueue+0x67/0x5e0
 ? verify_cpu+0xf0/0x100
 drain_workqueue+0xa0/0x110
 destroy_workqueue+0x36/0x250
 __loop_clr_fd+0x9a/0x660 [loop]
 ? blkdev_ioctl+0x8d/0x2a0
 block_ioctl+0x3f/0x50
 __x64_sys_ioctl+0x80/0xb0
 do_syscall_64+0x38/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
heftig pushed a commit that referenced this pull request Sep 12, 2021
When removing the device we call blkdev_put() on the device once we've
removed it, and because we have an EXCL open we need to take the
->open_mutex on the block device to clean it up.  Unfortunately during
device remove we are holding the sb writers lock, which results in the
following lockdep splat:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ torvalds#407 Not tainted
------------------------------------------------------
losetup/11595 is trying to acquire lock:
ffff973ac35dd138 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0

but task is already holding lock:
ffff973ac9812c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       lo_open+0x28/0x60 [loop]
       blkdev_get_whole+0x25/0xf0
       blkdev_get_by_dev.part.0+0x168/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       do_sys_openat2+0x7b/0x130
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #3 (&disk->open_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       blkdev_put+0x3a/0x220
       btrfs_rm_device.cold+0x62/0xe5
       btrfs_ioctl+0x2a31/0x2e70
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #2 (sb_writers#12){.+.+}-{0:0}:
       lo_write_bvec+0xc2/0x240 [loop]
       loop_process_work+0x238/0xd00 [loop]
       process_one_work+0x26b/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
       process_one_work+0x245/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
       __lock_acquire+0x10ea/0x1d90
       lock_acquire+0xb5/0x2b0
       flush_workqueue+0x91/0x5e0
       drain_workqueue+0xa0/0x110
       destroy_workqueue+0x36/0x250
       __loop_clr_fd+0x9a/0x660 [loop]
       block_ioctl+0x3f/0x50
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_mutex);
                               lock(&disk->open_mutex);
                               lock(&lo->lo_mutex);
  lock((wq_completion)loop0);

 *** DEADLOCK ***

1 lock held by losetup/11595:
 #0: ffff973ac9812c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

stack backtrace:
CPU: 0 PID: 11595 Comm: losetup Not tainted 5.14.0-rc2+ torvalds#407
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
 dump_stack_lvl+0x57/0x72
 check_noncircular+0xcf/0xf0
 ? stack_trace_save+0x3b/0x50
 __lock_acquire+0x10ea/0x1d90
 lock_acquire+0xb5/0x2b0
 ? flush_workqueue+0x67/0x5e0
 ? lockdep_init_map_type+0x47/0x220
 flush_workqueue+0x91/0x5e0
 ? flush_workqueue+0x67/0x5e0
 ? verify_cpu+0xf0/0x100
 drain_workqueue+0xa0/0x110
 destroy_workqueue+0x36/0x250
 __loop_clr_fd+0x9a/0x660 [loop]
 ? blkdev_ioctl+0x8d/0x2a0
 block_ioctl+0x3f/0x50
 __x64_sys_ioctl+0x80/0xb0
 do_syscall_64+0x38/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc21255d4cb

So instead save the bdev and do the put once we've dropped the sb
writers lock in order to avoid the lockdep recursion.

Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
heftig pushed a commit that referenced this pull request Sep 12, 2021
If CONFIG_BLK_DEV_LOOP && CONFIG_MTD (at least; there might be other
combinations), lockdep complains circular locking dependency at
__loop_clr_fd(), for major_names_lock serves as a locking dependency
aggregating hub across multiple block modules.

 ======================================================
 WARNING: possible circular locking dependency detected
 5.14.0+ torvalds#757 Tainted: G            E
 ------------------------------------------------------
 systemd-udevd/7568 is trying to acquire lock:
 ffff88800f334d48 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x70/0x560

 but task is already holding lock:
 ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&lo->lo_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_killable_nested+0x17/0x20
        lo_open+0x23/0x50 [loop]
        blkdev_get_by_dev+0x199/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #5 (&disk->open_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        bd_register_pending_holders+0x20/0x100
        device_add_disk+0x1ae/0x390
        loop_add+0x29c/0x2d0 [loop]
        blk_request_module+0x5a/0xb0
        blkdev_get_no_open+0x27/0xa0
        blkdev_get_by_dev+0x5f/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #4 (major_names_lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        blkdev_show+0x19/0x80
        devinfo_show+0x52/0x60
        seq_read_iter+0x2d5/0x3e0
        proc_reg_read_iter+0x41/0x80
        vfs_read+0x2ac/0x330
        ksys_read+0x6b/0xd0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #3 (&p->lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        seq_read_iter+0x37/0x3e0
        generic_file_splice_read+0xf3/0x170
        splice_direct_to_actor+0x14e/0x350
        do_splice_direct+0x84/0xd0
        do_sendfile+0x263/0x430
        __se_sys_sendfile64+0x96/0xc0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #2 (sb_writers#3){.+.+}-{0:0}:
        lock_acquire+0xbe/0x1f0
        lo_write_bvec+0x96/0x280 [loop]
        loop_process_work+0xa68/0xc10 [loop]
        process_one_work+0x293/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
        lock_acquire+0xbe/0x1f0
        process_one_work+0x280/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #0 ((wq_completion)loop0){+.+.}-{0:0}:
        validate_chain+0x1f0d/0x33e0
        __lock_acquire+0x92d/0x1030
        lock_acquire+0xbe/0x1f0
        flush_workqueue+0x8c/0x560
        drain_workqueue+0x80/0x140
        destroy_workqueue+0x47/0x4f0
        __loop_clr_fd+0xb4/0x400 [loop]
        blkdev_put+0x14a/0x1d0
        blkdev_close+0x1c/0x20
        __fput+0xfd/0x220
        task_work_run+0x69/0xc0
        exit_to_user_mode_prepare+0x1ce/0x1f0
        syscall_exit_to_user_mode+0x26/0x60
        do_syscall_64+0x4c/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 other info that might help us debug this:

 Chain exists of:
   (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&lo->lo_mutex);
                                lock(&disk->open_mutex);
                                lock(&lo->lo_mutex);
   lock((wq_completion)loop0);

  *** DEADLOCK ***

 2 locks held by systemd-udevd/7568:
  #0: ffff888012554128 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x4c/0x1d0
  #1: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 stack backtrace:
 CPU: 0 PID: 7568 Comm: systemd-udevd Tainted: G            E     5.14.0+ torvalds#757
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
 Call Trace:
  dump_stack_lvl+0x79/0xbf
  print_circular_bug+0x5d6/0x5e0
  ? stack_trace_save+0x42/0x60
  ? save_trace+0x3d/0x2d0
  check_noncircular+0x10b/0x120
  validate_chain+0x1f0d/0x33e0
  ? __lock_acquire+0x953/0x1030
  ? __lock_acquire+0x953/0x1030
  __lock_acquire+0x92d/0x1030
  ? flush_workqueue+0x70/0x560
  lock_acquire+0xbe/0x1f0
  ? flush_workqueue+0x70/0x560
  flush_workqueue+0x8c/0x560
  ? flush_workqueue+0x70/0x560
  ? sched_clock_cpu+0xe/0x1a0
  ? drain_workqueue+0x41/0x140
  drain_workqueue+0x80/0x140
  destroy_workqueue+0x47/0x4f0
  ? blk_mq_freeze_queue_wait+0xac/0xd0
  __loop_clr_fd+0xb4/0x400 [loop]
  ? __mutex_unlock_slowpath+0x35/0x230
  blkdev_put+0x14a/0x1d0
  blkdev_close+0x1c/0x20
  __fput+0xfd/0x220
  task_work_run+0x69/0xc0
  exit_to_user_mode_prepare+0x1ce/0x1f0
  syscall_exit_to_user_mode+0x26/0x60
  do_syscall_64+0x4c/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f0fd4c661f7
 Code: 00 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 13 fc ff ff
 RSP: 002b:00007ffd1c9e9fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 00007f0fd46be6c8 RCX: 00007f0fd4c661f7
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
 RBP: 0000000000000006 R08: 000055fff1eaf400 R09: 0000000000000000
 R10: 00007f0fd46be6c8 R11: 0000000000000246 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000002f08 R15: 00007ffd1c9ea050

Commit 1c500ad ("loop: reduce the loop_ctl_mutex scope") is for
breaking "loop_ctl_mutex => &lo->lo_mutex" dependency chain. But enabling
a different block module results in forming circular locking dependency
due to shared major_names_lock mutex.

The simplest fix is to call probe function without holding
major_names_lock [1], but Christoph Hellwig does not like such idea.
Therefore, instead of holding major_names_lock in blkdev_show(),
introduce a different lock for blkdev_show() in order to break
"sb_writers#$N => &p->lock => major_names_lock" dependency chain.

Link: https://lkml.kernel.org/r/[email protected] [1]
Signed-off-by: Tetsuo Handa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
heftig pushed a commit that referenced this pull request Sep 16, 2021
As previously noted in commit 66e4f4a ("rtc: cmos: Use
spin_lock_irqsave() in cmos_interrupt()"):

<4>[  254.192378] WARNING: inconsistent lock state
<4>[  254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ #1 Not tainted
<4>[  254.192396] --------------------------------
<4>[  254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
<4>[  254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes:
<4>[  254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100
<4>[  254.192481] {IN-HARDIRQ-W} state was registered at:
<4>[  254.192488]   lock_acquire+0xd1/0x3d0
<4>[  254.192504]   _raw_spin_lock+0x2a/0x40
<4>[  254.192519]   cmos_interrupt+0x18/0x100
<4>[  254.192536]   rtc_handler+0x1f/0xc0
<4>[  254.192553]   acpi_ev_fixed_event_detect+0x109/0x13c
<4>[  254.192574]   acpi_ev_sci_xrupt_handler+0xb/0x28
<4>[  254.192596]   acpi_irq+0x13/0x30
<4>[  254.192620]   __handle_irq_event_percpu+0x43/0x2c0
<4>[  254.192641]   handle_irq_event_percpu+0x2b/0x70
<4>[  254.192661]   handle_irq_event+0x2f/0x50
<4>[  254.192680]   handle_fasteoi_irq+0x9e/0x150
<4>[  254.192693]   __common_interrupt+0x76/0x140
<4>[  254.192715]   common_interrupt+0x96/0xc0
<4>[  254.192732]   asm_common_interrupt+0x1e/0x40
<4>[  254.192750]   _raw_spin_unlock_irqrestore+0x38/0x60
<4>[  254.192767]   resume_irqs+0xba/0xf0
<4>[  254.192786]   dpm_resume_noirq+0x245/0x3d0
<4>[  254.192811]   suspend_devices_and_enter+0x230/0xaa0
<4>[  254.192835]   pm_suspend.cold.8+0x301/0x34a
<4>[  254.192859]   state_store+0x7b/0xe0
<4>[  254.192879]   kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.192899]   new_sync_write+0x11d/0x1b0
<4>[  254.192916]   vfs_write+0x265/0x390
<4>[  254.192933]   ksys_write+0x5a/0xd0
<4>[  254.192949]   do_syscall_64+0x33/0x80
<4>[  254.192965]   entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.192986] irq event stamp: 43775
<4>[  254.192994] hardirqs last  enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0
<4>[  254.193049] softirqs last  enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e
<4>[  254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0
<4>[  254.193101]
                  other info that might help us debug this:
<4>[  254.193107]  Possible unsafe locking scenario:

<4>[  254.193112]        CPU0
<4>[  254.193117]        ----
<4>[  254.193121]   lock(rtc_lock);
<4>[  254.193137]   <Interrupt>
<4>[  254.193142]     lock(rtc_lock);
<4>[  254.193156]
                   *** DEADLOCK ***

<4>[  254.193161] 6 locks held by rtcwake/5309:
<4>[  254.193174]  #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0
<4>[  254.193232]  #1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0
<4>[  254.193282]  #2: ffff888100cef3c0 (kn->active#285
<7>[  254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled
<4>[  254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0
<4>[  254.193333]  #3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a
<4>[  254.193387]  #4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70
<4>[  254.193433]  #5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0
<4>[  254.193485]
                  stack backtrace:
<4>[  254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ #1
<4>[  254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019
<4>[  254.193524] Call Trace:
<4>[  254.193536]  dump_stack+0x7f/0xad
<4>[  254.193567]  mark_lock.part.47+0x8ca/0xce0
<4>[  254.193604]  __lock_acquire+0x39b/0x2590
<4>[  254.193626]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193660]  lock_acquire+0xd1/0x3d0
<4>[  254.193677]  ? cmos_interrupt+0x18/0x100
<4>[  254.193716]  _raw_spin_lock+0x2a/0x40
<4>[  254.193735]  ? cmos_interrupt+0x18/0x100
<4>[  254.193758]  cmos_interrupt+0x18/0x100
<4>[  254.193785]  cmos_resume+0x2ac/0x2d0
<4>[  254.193813]  ? acpi_pm_set_device_wakeup+0x1f/0x110
<4>[  254.193842]  ? pnp_bus_suspend+0x10/0x10
<4>[  254.193864]  pnp_bus_resume+0x5e/0x90
<4>[  254.193885]  dpm_run_callback+0x5f/0x240
<4>[  254.193914]  device_resume+0xb2/0x1e0
<4>[  254.193942]  ? pm_dev_err+0x25/0x25
<4>[  254.193974]  dpm_resume+0xea/0x3f0
<4>[  254.194005]  dpm_resume_end+0x8/0x10
<4>[  254.194030]  suspend_devices_and_enter+0x29b/0xaa0
<4>[  254.194066]  pm_suspend.cold.8+0x301/0x34a
<4>[  254.194094]  state_store+0x7b/0xe0
<4>[  254.194124]  kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.194151]  new_sync_write+0x11d/0x1b0
<4>[  254.194183]  vfs_write+0x265/0x390
<4>[  254.194207]  ksys_write+0x5a/0xd0
<4>[  254.194232]  do_syscall_64+0x33/0x80
<4>[  254.194251]  entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.194274] RIP: 0033:0x7f07d79691e7
<4>[  254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
<4>[  254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4>[  254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7
<4>[  254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b
<4>[  254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004
<4>[  254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004

which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough
to trigger the alarm during the suspend.

Fixes: 6950d04 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ")
References: 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"):
Signed-off-by: Chris Wilson <[email protected]>
Cc: Xiaofei Tan <[email protected]>
Cc: Alexandre Belloni <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
heftig pushed a commit that referenced this pull request Sep 22, 2021
It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  #1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  #2  0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  #3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  #4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  #5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  #6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
      at util/hist.c:1056
  #7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
  #8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  #9  0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
      at builtin-top.c:842
  torvalds#10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
  torvalds#11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  torvalds#12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  torvalds#13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
  torvalds#14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  torvalds#15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  torvalds#16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  torvalds#17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  torvalds#18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame #2, the code is:

488	 if (he->srcline) {
489          he->srcline = strdup(he->srcline);
490          if (he->srcline == NULL)
491              goto err_rawdata;
492	 }

If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent && !*parent &&
2183                     symbol__match_regex(al.sym, &parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees && root_al &&
2186                   symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al->map);
1219
1220         err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
1221                                         iter->evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter->ops->prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter->ops->add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter->ops->add_single_entry(iter, al);

will go on with al->srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!

Signed-off-by: Michael Petlan <[email protected]>
CC: Milian Wolff <[email protected]>
Cc: Jiri Olsa <[email protected]>
Fixes: 1fb7d06 ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/[email protected]
Reported-by: Juri Lelli <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
heftig pushed a commit that referenced this pull request Sep 22, 2021
FD uses xyarray__entry that may return NULL if an index is out of
bounds. If NULL is returned then a segv happens as FD unconditionally
dereferences the pointer. This was happening in a case of with perf
iostat as shown below. The fix is to make FD an "int*" rather than an
int and handle the NULL case as either invalid input or a closed fd.

  $ sudo gdb --args perf stat --iostat  list
  ...
  Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
  50      {
  (gdb) bt
   #0  perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
   #1  0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410,
      threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792
   #2  0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0)
      at util/evsel.c:2045
   #3  0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0)
      at util/evsel.c:2065
   #4  0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0,
      config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590
   #5  0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:833
   #6  0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:1048
   #7  0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534
   #8  0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3,
      argv=0x7fffffffe4a0) at perf.c:313
   #9  0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365
   torvalds#10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409
   torvalds#11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539
  ...
  (gdb) c
  Continuing.
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/).
  /bin/dmesg | grep -i perf may provide additional information.

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166
  166                     if (FD(evsel, cpu, thread) >= 0)

v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was
    backward.

Signed-off-by: Ian Rogers <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit 21e3980 ]

vctrl_enable() and vctrl_disable() call regulator_enable() and
regulator_disable(), respectively. However, vctrl_* are regulator ops
and should not be calling the locked regulator APIs. Doing so results in
a lockdep warning.

Instead of exporting more internal regulator ops, model the ctrl supply
as an actual supply to vctrl-regulator. At probe time this driver still
needs to use the consumer API to fetch its constraints, but otherwise
lets the regulator core handle the upstream supply for it.

The enable/disable/is_enabled ops are not removed, but now only track
state internally. This preserves the original behavior with the ops
being available, but one could argue that the original behavior was
already incorrect: the internal state would not match the upstream
supply if that supply had another consumer that enabled the supply,
while vctrl-regulator was not enabled.

The lockdep warning is as follows:

	WARNING: possible circular locking dependency detected
	5.14.0-rc6 archlinux#2 Not tainted
	------------------------------------------------------
	swapper/0/1 is trying to acquire lock:
	ffffffc011306d00 (regulator_list_mutex){+.+.}-{3:3}, at:
		regulator_lock_dependent (arch/arm64/include/asm/current.h:19
					  include/linux/ww_mutex.h:111
					  drivers/regulator/core.c:329)

	but task is already holding lock:
	ffffff8004a77160 (regulator_ww_class_mutex){+.+.}-{3:3}, at:
		regulator_lock_recursive (drivers/regulator/core.c:156
					  drivers/regulator/core.c:263)

	which lock already depends on the new lock.

	the existing dependency chain (in reverse order) is:

	-> archlinux#2 (regulator_ww_class_mutex){+.+.}-{3:3}:
	__mutex_lock_common (include/asm-generic/atomic-instrumented.h:606
			     include/asm-generic/atomic-long.h:29
			     kernel/locking/mutex.c:103
			     kernel/locking/mutex.c:144
			     kernel/locking/mutex.c:963)
	ww_mutex_lock (kernel/locking/mutex.c:1199)
	regulator_lock_recursive (drivers/regulator/core.c:156
				  drivers/regulator/core.c:263)
	regulator_lock_dependent (drivers/regulator/core.c:343)
	regulator_enable (drivers/regulator/core.c:2808)
	set_machine_constraints (drivers/regulator/core.c:1536)
	regulator_register (drivers/regulator/core.c:5486)
	devm_regulator_register (drivers/regulator/devres.c:196)
	reg_fixed_voltage_probe (drivers/regulator/fixed.c:289)
	platform_probe (drivers/base/platform.c:1427)
	[...]

	-> archlinux#1 (regulator_ww_class_acquire){+.+.}-{0:0}:
	regulator_lock_dependent (include/linux/ww_mutex.h:129
				  drivers/regulator/core.c:329)
	regulator_enable (drivers/regulator/core.c:2808)
	set_machine_constraints (drivers/regulator/core.c:1536)
	regulator_register (drivers/regulator/core.c:5486)
	devm_regulator_register (drivers/regulator/devres.c:196)
	reg_fixed_voltage_probe (drivers/regulator/fixed.c:289)
	[...]

	-> #0 (regulator_list_mutex){+.+.}-{3:3}:
	__lock_acquire (kernel/locking/lockdep.c:3052 (discriminator 4)
			kernel/locking/lockdep.c:3174 (discriminator 4)
			kernel/locking/lockdep.c:3789 (discriminator 4)
			kernel/locking/lockdep.c:5015 (discriminator 4))
	lock_acquire (arch/arm64/include/asm/percpu.h:39
		      kernel/locking/lockdep.c:438
		      kernel/locking/lockdep.c:5627)
	__mutex_lock_common (include/asm-generic/atomic-instrumented.h:606
			     include/asm-generic/atomic-long.h:29
			     kernel/locking/mutex.c:103
			     kernel/locking/mutex.c:144
			     kernel/locking/mutex.c:963)
	mutex_lock_nested (kernel/locking/mutex.c:1125)
	regulator_lock_dependent (arch/arm64/include/asm/current.h:19
				  include/linux/ww_mutex.h:111
				  drivers/regulator/core.c:329)
	regulator_enable (drivers/regulator/core.c:2808)
	vctrl_enable (drivers/regulator/vctrl-regulator.c:400)
	_regulator_do_enable (drivers/regulator/core.c:2617)
	_regulator_enable (drivers/regulator/core.c:2764)
	regulator_enable (drivers/regulator/core.c:308
			  drivers/regulator/core.c:2809)
	_set_opp (drivers/opp/core.c:819 drivers/opp/core.c:1072)
	dev_pm_opp_set_rate (drivers/opp/core.c:1164)
	set_target (drivers/cpufreq/cpufreq-dt.c:62)
	__cpufreq_driver_target (drivers/cpufreq/cpufreq.c:2216
				 drivers/cpufreq/cpufreq.c:2271)
	cpufreq_online (drivers/cpufreq/cpufreq.c:1488 (discriminator 2))
	cpufreq_add_dev (drivers/cpufreq/cpufreq.c:1563)
	subsys_interface_register (drivers/base/bus.c:?)
	cpufreq_register_driver (drivers/cpufreq/cpufreq.c:2819)
	dt_cpufreq_probe (drivers/cpufreq/cpufreq-dt.c:344)
	[...]

	other info that might help us debug this:

	Chain exists of:
	  regulator_list_mutex --> regulator_ww_class_acquire --> regulator_ww_class_mutex

	 Possible unsafe locking scenario:

	       CPU0                    CPU1
	       ----                    ----
	  lock(regulator_ww_class_mutex);
				       lock(regulator_ww_class_acquire);
				       lock(regulator_ww_class_mutex);
	  lock(regulator_list_mutex);

	 *** DEADLOCK ***

	6 locks held by swapper/0/1:
	#0: ffffff8002d32188 (&dev->mutex){....}-{3:3}, at:
		__device_driver_lock (drivers/base/dd.c:1030)
	archlinux#1: ffffffc0111a0520 (cpu_hotplug_lock){++++}-{0:0}, at:
		cpufreq_register_driver (drivers/cpufreq/cpufreq.c:2792 (discriminator 2))
	archlinux#2: ffffff8002a8d918 (subsys mutex#9){+.+.}-{3:3}, at:
		subsys_interface_register (drivers/base/bus.c:1033)
	archlinux#3: ffffff800341bb90 (&policy->rwsem){+.+.}-{3:3}, at:
		cpufreq_online (include/linux/bitmap.h:285
				include/linux/cpumask.h:405
				drivers/cpufreq/cpufreq.c:1399)
	archlinux#4: ffffffc011f0b7b8 (regulator_ww_class_acquire){+.+.}-{0:0}, at:
		regulator_enable (drivers/regulator/core.c:2808)
	archlinux#5: ffffff8004a77160 (regulator_ww_class_mutex){+.+.}-{3:3}, at:
		regulator_lock_recursive (drivers/regulator/core.c:156
		drivers/regulator/core.c:263)

	stack backtrace:
	CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.14.0-rc6 archlinux#2 7c8f8996d021ed0f65271e6aeebf7999de74a9fa
	Hardware name: Google Scarlet (DT)
	Call trace:
	dump_backtrace (arch/arm64/kernel/stacktrace.c:161)
	show_stack (arch/arm64/kernel/stacktrace.c:218)
	dump_stack_lvl (lib/dump_stack.c:106 (discriminator 2))
	dump_stack (lib/dump_stack.c:113)
	print_circular_bug (kernel/locking/lockdep.c:?)
	check_noncircular (kernel/locking/lockdep.c:?)
	__lock_acquire (kernel/locking/lockdep.c:3052 (discriminator 4)
			kernel/locking/lockdep.c:3174 (discriminator 4)
			kernel/locking/lockdep.c:3789 (discriminator 4)
			kernel/locking/lockdep.c:5015 (discriminator 4))
	lock_acquire (arch/arm64/include/asm/percpu.h:39
		      kernel/locking/lockdep.c:438
		      kernel/locking/lockdep.c:5627)
	__mutex_lock_common (include/asm-generic/atomic-instrumented.h:606
			     include/asm-generic/atomic-long.h:29
			     kernel/locking/mutex.c:103
			     kernel/locking/mutex.c:144
			     kernel/locking/mutex.c:963)
	mutex_lock_nested (kernel/locking/mutex.c:1125)
	regulator_lock_dependent (arch/arm64/include/asm/current.h:19
				  include/linux/ww_mutex.h:111
				  drivers/regulator/core.c:329)
	regulator_enable (drivers/regulator/core.c:2808)
	vctrl_enable (drivers/regulator/vctrl-regulator.c:400)
	_regulator_do_enable (drivers/regulator/core.c:2617)
	_regulator_enable (drivers/regulator/core.c:2764)
	regulator_enable (drivers/regulator/core.c:308
			  drivers/regulator/core.c:2809)
	_set_opp (drivers/opp/core.c:819 drivers/opp/core.c:1072)
	dev_pm_opp_set_rate (drivers/opp/core.c:1164)
	set_target (drivers/cpufreq/cpufreq-dt.c:62)
	__cpufreq_driver_target (drivers/cpufreq/cpufreq.c:2216
				 drivers/cpufreq/cpufreq.c:2271)
	cpufreq_online (drivers/cpufreq/cpufreq.c:1488 (discriminator 2))
	cpufreq_add_dev (drivers/cpufreq/cpufreq.c:1563)
	subsys_interface_register (drivers/base/bus.c:?)
	cpufreq_register_driver (drivers/cpufreq/cpufreq.c:2819)
	dt_cpufreq_probe (drivers/cpufreq/cpufreq-dt.c:344)
	[...]

Reported-by: Brian Norris <[email protected]>
Fixes: f8702f9 ("regulator: core: Use ww_mutex for regulators locking")
Fixes: e915331 ("regulator: vctrl-regulator: Avoid deadlock getting and setting the voltage")
Signed-off-by: Chen-Yu Tsai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit 6fa54bc ]

If em28xx_ir_init fails, it would decrease the refcount of dev. However,
in the em28xx_ir_fini, when ir is NULL, it goes to ref_put and decrease
the refcount of dev. This will lead to a refcount bug.

Fix this bug by removing the kref_put in the error handling code
of em28xx_ir_init.

refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x18e/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.13.0 archlinux#3
Workqueue: usb_hub_wq hub_event
RIP: 0010:refcount_warn_saturate+0x18e/0x1a0 lib/refcount.c:28
Call Trace:
  kref_put.constprop.0+0x60/0x85 include/linux/kref.h:69
  em28xx_usb_disconnect.cold+0xd7/0xdc drivers/media/usb/em28xx/em28xx-cards.c:4150
  usb_unbind_interface+0xbf/0x3a0 drivers/usb/core/driver.c:458
  __device_release_driver drivers/base/dd.c:1201 [inline]
  device_release_driver_internal+0x22a/0x230 drivers/base/dd.c:1232
  bus_remove_device+0x108/0x160 drivers/base/bus.c:529
  device_del+0x1fe/0x510 drivers/base/core.c:3540
  usb_disable_device+0xd1/0x1d0 drivers/usb/core/message.c:1419
  usb_disconnect+0x109/0x330 drivers/usb/core/hub.c:2221
  hub_port_connect drivers/usb/core/hub.c:5151 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5440 [inline]
  port_event drivers/usb/core/hub.c:5586 [inline]
  hub_event+0xf81/0x1d40 drivers/usb/core/hub.c:5668
  process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
  process_scheduled_works kernel/workqueue.c:2338 [inline]
  worker_thread+0x333/0x5b0 kernel/workqueue.c:2424
  kthread+0x188/0x1d0 kernel/kthread.c:319
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Reported-by: Dongliang Mu <[email protected]>
Fixes: ac56886 ("media: em28xx: Fix possible memory leak of em28xx struct")
Signed-off-by: Dongliang Mu <[email protected]>
Signed-off-by: Sean Young <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
commit 13be2ef upstream.

As previously noted in commit 66e4f4a ("rtc: cmos: Use
spin_lock_irqsave() in cmos_interrupt()"):

<4>[  254.192378] WARNING: inconsistent lock state
<4>[  254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ archlinux#1 Not tainted
<4>[  254.192396] --------------------------------
<4>[  254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
<4>[  254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes:
<4>[  254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100
<4>[  254.192481] {IN-HARDIRQ-W} state was registered at:
<4>[  254.192488]   lock_acquire+0xd1/0x3d0
<4>[  254.192504]   _raw_spin_lock+0x2a/0x40
<4>[  254.192519]   cmos_interrupt+0x18/0x100
<4>[  254.192536]   rtc_handler+0x1f/0xc0
<4>[  254.192553]   acpi_ev_fixed_event_detect+0x109/0x13c
<4>[  254.192574]   acpi_ev_sci_xrupt_handler+0xb/0x28
<4>[  254.192596]   acpi_irq+0x13/0x30
<4>[  254.192620]   __handle_irq_event_percpu+0x43/0x2c0
<4>[  254.192641]   handle_irq_event_percpu+0x2b/0x70
<4>[  254.192661]   handle_irq_event+0x2f/0x50
<4>[  254.192680]   handle_fasteoi_irq+0x9e/0x150
<4>[  254.192693]   __common_interrupt+0x76/0x140
<4>[  254.192715]   common_interrupt+0x96/0xc0
<4>[  254.192732]   asm_common_interrupt+0x1e/0x40
<4>[  254.192750]   _raw_spin_unlock_irqrestore+0x38/0x60
<4>[  254.192767]   resume_irqs+0xba/0xf0
<4>[  254.192786]   dpm_resume_noirq+0x245/0x3d0
<4>[  254.192811]   suspend_devices_and_enter+0x230/0xaa0
<4>[  254.192835]   pm_suspend.cold.8+0x301/0x34a
<4>[  254.192859]   state_store+0x7b/0xe0
<4>[  254.192879]   kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.192899]   new_sync_write+0x11d/0x1b0
<4>[  254.192916]   vfs_write+0x265/0x390
<4>[  254.192933]   ksys_write+0x5a/0xd0
<4>[  254.192949]   do_syscall_64+0x33/0x80
<4>[  254.192965]   entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.192986] irq event stamp: 43775
<4>[  254.192994] hardirqs last  enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0
<4>[  254.193049] softirqs last  enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e
<4>[  254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0
<4>[  254.193101]
                  other info that might help us debug this:
<4>[  254.193107]  Possible unsafe locking scenario:

<4>[  254.193112]        CPU0
<4>[  254.193117]        ----
<4>[  254.193121]   lock(rtc_lock);
<4>[  254.193137]   <Interrupt>
<4>[  254.193142]     lock(rtc_lock);
<4>[  254.193156]
                   *** DEADLOCK ***

<4>[  254.193161] 6 locks held by rtcwake/5309:
<4>[  254.193174]  #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0
<4>[  254.193232]  archlinux#1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0
<4>[  254.193282]  archlinux#2: ffff888100cef3c0 (kn->active#285
<7>[  254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled
<4>[  254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0
<4>[  254.193333]  archlinux#3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a
<4>[  254.193387]  archlinux#4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70
<4>[  254.193433]  archlinux#5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0
<4>[  254.193485]
                  stack backtrace:
<4>[  254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ archlinux#1
<4>[  254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019
<4>[  254.193524] Call Trace:
<4>[  254.193536]  dump_stack+0x7f/0xad
<4>[  254.193567]  mark_lock.part.47+0x8ca/0xce0
<4>[  254.193604]  __lock_acquire+0x39b/0x2590
<4>[  254.193626]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193660]  lock_acquire+0xd1/0x3d0
<4>[  254.193677]  ? cmos_interrupt+0x18/0x100
<4>[  254.193716]  _raw_spin_lock+0x2a/0x40
<4>[  254.193735]  ? cmos_interrupt+0x18/0x100
<4>[  254.193758]  cmos_interrupt+0x18/0x100
<4>[  254.193785]  cmos_resume+0x2ac/0x2d0
<4>[  254.193813]  ? acpi_pm_set_device_wakeup+0x1f/0x110
<4>[  254.193842]  ? pnp_bus_suspend+0x10/0x10
<4>[  254.193864]  pnp_bus_resume+0x5e/0x90
<4>[  254.193885]  dpm_run_callback+0x5f/0x240
<4>[  254.193914]  device_resume+0xb2/0x1e0
<4>[  254.193942]  ? pm_dev_err+0x25/0x25
<4>[  254.193974]  dpm_resume+0xea/0x3f0
<4>[  254.194005]  dpm_resume_end+0x8/0x10
<4>[  254.194030]  suspend_devices_and_enter+0x29b/0xaa0
<4>[  254.194066]  pm_suspend.cold.8+0x301/0x34a
<4>[  254.194094]  state_store+0x7b/0xe0
<4>[  254.194124]  kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.194151]  new_sync_write+0x11d/0x1b0
<4>[  254.194183]  vfs_write+0x265/0x390
<4>[  254.194207]  ksys_write+0x5a/0xd0
<4>[  254.194232]  do_syscall_64+0x33/0x80
<4>[  254.194251]  entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.194274] RIP: 0033:0x7f07d79691e7
<4>[  254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
<4>[  254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4>[  254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7
<4>[  254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b
<4>[  254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004
<4>[  254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004

which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough
to trigger the alarm during the suspend.

Fixes: 6950d04 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ")
References: 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"):
Signed-off-by: Chris Wilson <[email protected]>
Cc: Xiaofei Tan <[email protected]>
Cc: Alexandre Belloni <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
commit 57f0ff0 upstream.

It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  archlinux#1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  archlinux#2  0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  archlinux#3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  archlinux#4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  archlinux#5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  archlinux#6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
      at util/hist.c:1056
  archlinux#7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
  archlinux#8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  archlinux#9  0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
      at builtin-top.c:842
  torvalds#10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
  torvalds#11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  torvalds#12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  torvalds#13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
  torvalds#14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  torvalds#15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  torvalds#16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  torvalds#17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  torvalds#18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame archlinux#2, the code is:

488	 if (he->srcline) {
489          he->srcline = strdup(he->srcline);
490          if (he->srcline == NULL)
491              goto err_rawdata;
492	 }

If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent && !*parent &&
2183                     symbol__match_regex(al.sym, &parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees && root_al &&
2186                   symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al->map);
1219
1220         err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
1221                                         iter->evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter->ops->prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter->ops->add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter->ops->add_single_entry(iter, al);

will go on with al->srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!

Signed-off-by: Michael Petlan <[email protected]>
CC: Milian Wolff <[email protected]>
Cc: Jiri Olsa <[email protected]>
Fixes: 1fb7d06 ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/[email protected]
Reported-by: Juri Lelli <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit 340fa66 ]

Recent changes exposed a bug where specifically-timed requests to the
path manager netlink API could trigger a divide-by-zero in
__tcp_select_window(), as syzkaller does:

divide error: 0000 [archlinux#1] SMP KASAN NOPTI
CPU: 0 PID: 9667 Comm: syz-executor.0 Not tainted 5.14.0-rc6+ archlinux#3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:__tcp_select_window+0x509/0xa60 net/ipv4/tcp_output.c:3016
Code: 44 89 ff e8 c9 29 e9 fd 45 39 e7 0f 8d 20 ff ff ff e8 db 28 e9 fd 44 89 e3 e9 13 ff ff ff e8 ce 28 e9 fd 44 89 e0 44 89 e3 99 <f7> 7c 24 04 29 d3 e9 fc fe ff ff e8 b7 28 e9 fd 44 89 f1 48 89 ea
RSP: 0018:ffff888031ccf020 EFLAGS: 00010216
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000
RDX: 0000000000000000 RSI: ffff88811532c080 RDI: 0000000000000002
RBP: 0000000000000000 R08: ffffffff835807c2 R09: 0000000000000000
R10: 0000000000000004 R11: ffffed1020b92441 R12: 0000000000000000
R13: 1ffff11006399e08 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fa4c8344700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f424000 CR3: 000000003e4e2003 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
 tcp_select_window net/ipv4/tcp_output.c:264 [inline]
 __tcp_transmit_skb+0xc00/0x37a0 net/ipv4/tcp_output.c:1351
 __tcp_send_ack.part.0+0x3ec/0x760 net/ipv4/tcp_output.c:3972
 __tcp_send_ack net/ipv4/tcp_output.c:3978 [inline]
 tcp_send_ack+0x7d/0xa0 net/ipv4/tcp_output.c:3978
 mptcp_pm_nl_addr_send_ack+0x1ab/0x380 net/mptcp/pm_netlink.c:654
 mptcp_pm_remove_addr+0x161/0x200 net/mptcp/pm.c:58
 mptcp_nl_remove_id_zero_address+0x197/0x460 net/mptcp/pm_netlink.c:1328
 mptcp_nl_cmd_del_addr+0x98b/0xd40 net/mptcp/pm_netlink.c:1359
 genl_family_rcv_msg_doit.isra.0+0x225/0x340 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x341/0x5b0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x148/0x430 net/netlink/af_netlink.c:2504
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x537/0x750 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x846/0xd80 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0x14e/0x190 net/socket.c:724
 ____sys_sendmsg+0x709/0x870 net/socket.c:2403
 ___sys_sendmsg+0xff/0x170 net/socket.c:2457
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

mptcp_pm_nl_addr_send_ack() was attempting to send a TCP ACK on the
first subflow in the MPTCP socket's connection list without validating
that the subflow was in a suitable connection state. To address this,
always validate subflow state when sending extra ACKs on subflows
for address advertisement or subflow priority change.

Fixes: 84dfe36 ("mptcp: send out dedicated ADD_ADDR packet")
Closes: multipath-tcp/mptcp_net-next#229
Co-developed-by: Paolo Abeni <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Acked-by: Geliang Tang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
commit 98e2e40 upstream.

When the refcount is decreased to 0, the resource reclamation branch is
entered.  Before CPU0 reaches the race point (1), CPU1 may obtain the
spinlock and traverse the rbtree to find 'root', see
nilfs_lookup_root().

Although CPU1 will call refcount_inc() to increase the refcount, it is
obviously too late.  CPU0 will release 'root' directly, CPU1 then
accesses 'root' and triggers UAF.

Use refcount_dec_and_lock() to ensure that both the operations of
decrease refcount to 0 and link deletion are lock protected eliminates
this risk.

	     CPU0                      CPU1
	nilfs_put_root():
		    <-------- (1)
				spin_lock(&nilfs->ns_cptree_lock);
				rb_erase(&root->rb_node, &nilfs->ns_cptree);
				spin_unlock(&nilfs->ns_cptree_lock);

	kfree(root);
		    <-------- use-after-free

  refcount_t: underflow; use-after-free.
  WARNING: CPU: 2 PID: 9476 at lib/refcount.c:28 \
  refcount_warn_saturate+0x1cf/0x210 lib/refcount.c:28
  Modules linked in:
  CPU: 2 PID: 9476 Comm: syz-executor.0 Not tainted 5.10.45-rc1+ archlinux#3
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
  RIP: 0010:refcount_warn_saturate+0x1cf/0x210 lib/refcount.c:28
  ... ...
  Call Trace:
     __refcount_sub_and_test include/linux/refcount.h:283 [inline]
     __refcount_dec_and_test include/linux/refcount.h:315 [inline]
     refcount_dec_and_test include/linux/refcount.h:333 [inline]
     nilfs_put_root+0xc1/0xd0 fs/nilfs2/the_nilfs.c:795
     nilfs_segctor_destroy fs/nilfs2/segment.c:2749 [inline]
     nilfs_detach_log_writer+0x3fa/0x570 fs/nilfs2/segment.c:2812
     nilfs_put_super+0x2f/0xf0 fs/nilfs2/super.c:467
     generic_shutdown_super+0xcd/0x1f0 fs/super.c:464
     kill_block_super+0x4a/0x90 fs/super.c:1446
     deactivate_locked_super+0x6a/0xb0 fs/super.c:335
     deactivate_super+0x85/0x90 fs/super.c:366
     cleanup_mnt+0x277/0x2e0 fs/namespace.c:1118
     __cleanup_mnt+0x15/0x20 fs/namespace.c:1125
     task_work_run+0x8e/0x110 kernel/task_work.c:151
     tracehook_notify_resume include/linux/tracehook.h:188 [inline]
     exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
     exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
     syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
     do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
     entry_SYSCALL_64_after_hwframe+0x44/0xa9

There is no reproduction program, and the above is only theoretical
analysis.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: ba65ae4 ("nilfs2: add checkpoint tree to nilfs object")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Zhen Lei <[email protected]>
Signed-off-by: Ryusuke Konishi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit 8f96a5b ]

We update the ctime/mtime of a block device when we remove it so that
blkid knows the device changed.  However we do this by re-opening the
block device and calling filp_update_time.  This is more correct because
it'll call the inode->i_op->update_time if it exists, but the block dev
inodes do not do this.  Instead call generic_update_time() on the
bd_inode in order to avoid the blkdev_open path and get rid of the
following lockdep splat:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ torvalds#406 Not tainted
------------------------------------------------------
losetup/11596 is trying to acquire lock:
ffff939640d2f538 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0

but task is already holding lock:
ffff939655510c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> archlinux#4 (&lo->lo_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       lo_open+0x28/0x60 [loop]
       blkdev_get_whole+0x25/0xf0
       blkdev_get_by_dev.part.0+0x168/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       do_sys_openat2+0x7b/0x130
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> archlinux#3 (&disk->open_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       blkdev_get_by_dev.part.0+0x56/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       file_open_name+0xc7/0x170
       filp_open+0x2c/0x50
       btrfs_scratch_superblocks.part.0+0x10f/0x170
       btrfs_rm_device.cold+0xe8/0xed
       btrfs_ioctl+0x2a31/0x2e70
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> archlinux#2 (sb_writers#12){.+.+}-{0:0}:
       lo_write_bvec+0xc2/0x240 [loop]
       loop_process_work+0x238/0xd00 [loop]
       process_one_work+0x26b/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> archlinux#1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
       process_one_work+0x245/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
       __lock_acquire+0x10ea/0x1d90
       lock_acquire+0xb5/0x2b0
       flush_workqueue+0x91/0x5e0
       drain_workqueue+0xa0/0x110
       destroy_workqueue+0x36/0x250
       __loop_clr_fd+0x9a/0x660 [loop]
       block_ioctl+0x3f/0x50
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_mutex);
                               lock(&disk->open_mutex);
                               lock(&lo->lo_mutex);
  lock((wq_completion)loop0);

 *** DEADLOCK ***

1 lock held by losetup/11596:
 #0: ffff939655510c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

stack backtrace:
CPU: 1 PID: 11596 Comm: losetup Not tainted 5.14.0-rc2+ torvalds#406
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
 dump_stack_lvl+0x57/0x72
 check_noncircular+0xcf/0xf0
 ? stack_trace_save+0x3b/0x50
 __lock_acquire+0x10ea/0x1d90
 lock_acquire+0xb5/0x2b0
 ? flush_workqueue+0x67/0x5e0
 ? lockdep_init_map_type+0x47/0x220
 flush_workqueue+0x91/0x5e0
 ? flush_workqueue+0x67/0x5e0
 ? verify_cpu+0xf0/0x100
 drain_workqueue+0xa0/0x110
 destroy_workqueue+0x36/0x250
 __loop_clr_fd+0x9a/0x660 [loop]
 ? blkdev_ioctl+0x8d/0x2a0
 block_ioctl+0x3f/0x50
 __x64_sys_ioctl+0x80/0xb0
 do_syscall_64+0x38/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit 3fa421d ]

When removing the device we call blkdev_put() on the device once we've
removed it, and because we have an EXCL open we need to take the
->open_mutex on the block device to clean it up.  Unfortunately during
device remove we are holding the sb writers lock, which results in the
following lockdep splat:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ torvalds#407 Not tainted
------------------------------------------------------
losetup/11595 is trying to acquire lock:
ffff973ac35dd138 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0

but task is already holding lock:
ffff973ac9812c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> archlinux#4 (&lo->lo_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       lo_open+0x28/0x60 [loop]
       blkdev_get_whole+0x25/0xf0
       blkdev_get_by_dev.part.0+0x168/0x3c0
       blkdev_open+0xd2/0xe0
       do_dentry_open+0x161/0x390
       path_openat+0x3cc/0xa20
       do_filp_open+0x96/0x120
       do_sys_openat2+0x7b/0x130
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> archlinux#3 (&disk->open_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7d/0x750
       blkdev_put+0x3a/0x220
       btrfs_rm_device.cold+0x62/0xe5
       btrfs_ioctl+0x2a31/0x2e70
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> archlinux#2 (sb_writers#12){.+.+}-{0:0}:
       lo_write_bvec+0xc2/0x240 [loop]
       loop_process_work+0x238/0xd00 [loop]
       process_one_work+0x26b/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> archlinux#1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
       process_one_work+0x245/0x560
       worker_thread+0x55/0x3c0
       kthread+0x140/0x160
       ret_from_fork+0x1f/0x30

-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
       __lock_acquire+0x10ea/0x1d90
       lock_acquire+0xb5/0x2b0
       flush_workqueue+0x91/0x5e0
       drain_workqueue+0xa0/0x110
       destroy_workqueue+0x36/0x250
       __loop_clr_fd+0x9a/0x660 [loop]
       block_ioctl+0x3f/0x50
       __x64_sys_ioctl+0x80/0xb0
       do_syscall_64+0x38/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_mutex);
                               lock(&disk->open_mutex);
                               lock(&lo->lo_mutex);
  lock((wq_completion)loop0);

 *** DEADLOCK ***

1 lock held by losetup/11595:
 #0: ffff973ac9812c68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]

stack backtrace:
CPU: 0 PID: 11595 Comm: losetup Not tainted 5.14.0-rc2+ torvalds#407
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
 dump_stack_lvl+0x57/0x72
 check_noncircular+0xcf/0xf0
 ? stack_trace_save+0x3b/0x50
 __lock_acquire+0x10ea/0x1d90
 lock_acquire+0xb5/0x2b0
 ? flush_workqueue+0x67/0x5e0
 ? lockdep_init_map_type+0x47/0x220
 flush_workqueue+0x91/0x5e0
 ? flush_workqueue+0x67/0x5e0
 ? verify_cpu+0xf0/0x100
 drain_workqueue+0xa0/0x110
 destroy_workqueue+0x36/0x250
 __loop_clr_fd+0x9a/0x660 [loop]
 ? blkdev_ioctl+0x8d/0x2a0
 block_ioctl+0x3f/0x50
 __x64_sys_ioctl+0x80/0xb0
 do_syscall_64+0x38/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc21255d4cb

So instead save the bdev and do the put once we've dropped the sb
writers lock in order to avoid the lockdep recursion.

Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit dfbb340 ]

If CONFIG_BLK_DEV_LOOP && CONFIG_MTD (at least; there might be other
combinations), lockdep complains circular locking dependency at
__loop_clr_fd(), for major_names_lock serves as a locking dependency
aggregating hub across multiple block modules.

 ======================================================
 WARNING: possible circular locking dependency detected
 5.14.0+ torvalds#757 Tainted: G            E
 ------------------------------------------------------
 systemd-udevd/7568 is trying to acquire lock:
 ffff88800f334d48 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x70/0x560

 but task is already holding lock:
 ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> archlinux#6 (&lo->lo_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_killable_nested+0x17/0x20
        lo_open+0x23/0x50 [loop]
        blkdev_get_by_dev+0x199/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> archlinux#5 (&disk->open_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        bd_register_pending_holders+0x20/0x100
        device_add_disk+0x1ae/0x390
        loop_add+0x29c/0x2d0 [loop]
        blk_request_module+0x5a/0xb0
        blkdev_get_no_open+0x27/0xa0
        blkdev_get_by_dev+0x5f/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> archlinux#4 (major_names_lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        blkdev_show+0x19/0x80
        devinfo_show+0x52/0x60
        seq_read_iter+0x2d5/0x3e0
        proc_reg_read_iter+0x41/0x80
        vfs_read+0x2ac/0x330
        ksys_read+0x6b/0xd0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> archlinux#3 (&p->lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        seq_read_iter+0x37/0x3e0
        generic_file_splice_read+0xf3/0x170
        splice_direct_to_actor+0x14e/0x350
        do_splice_direct+0x84/0xd0
        do_sendfile+0x263/0x430
        __se_sys_sendfile64+0x96/0xc0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> archlinux#2 (sb_writers#3){.+.+}-{0:0}:
        lock_acquire+0xbe/0x1f0
        lo_write_bvec+0x96/0x280 [loop]
        loop_process_work+0xa68/0xc10 [loop]
        process_one_work+0x293/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> archlinux#1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
        lock_acquire+0xbe/0x1f0
        process_one_work+0x280/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #0 ((wq_completion)loop0){+.+.}-{0:0}:
        validate_chain+0x1f0d/0x33e0
        __lock_acquire+0x92d/0x1030
        lock_acquire+0xbe/0x1f0
        flush_workqueue+0x8c/0x560
        drain_workqueue+0x80/0x140
        destroy_workqueue+0x47/0x4f0
        __loop_clr_fd+0xb4/0x400 [loop]
        blkdev_put+0x14a/0x1d0
        blkdev_close+0x1c/0x20
        __fput+0xfd/0x220
        task_work_run+0x69/0xc0
        exit_to_user_mode_prepare+0x1ce/0x1f0
        syscall_exit_to_user_mode+0x26/0x60
        do_syscall_64+0x4c/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 other info that might help us debug this:

 Chain exists of:
   (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&lo->lo_mutex);
                                lock(&disk->open_mutex);
                                lock(&lo->lo_mutex);
   lock((wq_completion)loop0);

  *** DEADLOCK ***

 2 locks held by systemd-udevd/7568:
  #0: ffff888012554128 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x4c/0x1d0
  archlinux#1: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 stack backtrace:
 CPU: 0 PID: 7568 Comm: systemd-udevd Tainted: G            E     5.14.0+ torvalds#757
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
 Call Trace:
  dump_stack_lvl+0x79/0xbf
  print_circular_bug+0x5d6/0x5e0
  ? stack_trace_save+0x42/0x60
  ? save_trace+0x3d/0x2d0
  check_noncircular+0x10b/0x120
  validate_chain+0x1f0d/0x33e0
  ? __lock_acquire+0x953/0x1030
  ? __lock_acquire+0x953/0x1030
  __lock_acquire+0x92d/0x1030
  ? flush_workqueue+0x70/0x560
  lock_acquire+0xbe/0x1f0
  ? flush_workqueue+0x70/0x560
  flush_workqueue+0x8c/0x560
  ? flush_workqueue+0x70/0x560
  ? sched_clock_cpu+0xe/0x1a0
  ? drain_workqueue+0x41/0x140
  drain_workqueue+0x80/0x140
  destroy_workqueue+0x47/0x4f0
  ? blk_mq_freeze_queue_wait+0xac/0xd0
  __loop_clr_fd+0xb4/0x400 [loop]
  ? __mutex_unlock_slowpath+0x35/0x230
  blkdev_put+0x14a/0x1d0
  blkdev_close+0x1c/0x20
  __fput+0xfd/0x220
  task_work_run+0x69/0xc0
  exit_to_user_mode_prepare+0x1ce/0x1f0
  syscall_exit_to_user_mode+0x26/0x60
  do_syscall_64+0x4c/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f0fd4c661f7
 Code: 00 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 13 fc ff ff
 RSP: 002b:00007ffd1c9e9fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 00007f0fd46be6c8 RCX: 00007f0fd4c661f7
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
 RBP: 0000000000000006 R08: 000055fff1eaf400 R09: 0000000000000000
 R10: 00007f0fd46be6c8 R11: 0000000000000246 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000002f08 R15: 00007ffd1c9ea050

Commit 1c500ad ("loop: reduce the loop_ctl_mutex scope") is for
breaking "loop_ctl_mutex => &lo->lo_mutex" dependency chain. But enabling
a different block module results in forming circular locking dependency
due to shared major_names_lock mutex.

The simplest fix is to call probe function without holding
major_names_lock [1], but Christoph Hellwig does not like such idea.
Therefore, instead of holding major_names_lock in blkdev_show(),
introduce a different lock for blkdev_show() in order to break
"sb_writers#$N => &p->lock => major_names_lock" dependency chain.

Link: https://lkml.kernel.org/r/[email protected] [1]
Signed-off-by: Tetsuo Handa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
dmdemoura pushed a commit to dmdemoura/linux that referenced this pull request Oct 6, 2021
[ Upstream commit aba5dae ]

FD uses xyarray__entry that may return NULL if an index is out of
bounds. If NULL is returned then a segv happens as FD unconditionally
dereferences the pointer. This was happening in a case of with perf
iostat as shown below. The fix is to make FD an "int*" rather than an
int and handle the NULL case as either invalid input or a closed fd.

  $ sudo gdb --args perf stat --iostat  list
  ...
  Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
  50      {
  (gdb) bt
   #0  perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
   archlinux#1  0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410,
      threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792
   archlinux#2  0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0)
      at util/evsel.c:2045
   archlinux#3  0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0)
      at util/evsel.c:2065
   archlinux#4  0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0,
      config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590
   archlinux#5  0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:833
   archlinux#6  0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:1048
   archlinux#7  0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534
   archlinux#8  0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3,
      argv=0x7fffffffe4a0) at perf.c:313
   archlinux#9  0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365
   torvalds#10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409
   torvalds#11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539
  ...
  (gdb) c
  Continuing.
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/).
  /bin/dmesg | grep -i perf may provide additional information.

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166
  166                     if (FD(evsel, cpu, thread) >= 0)

v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was
    backward.

Signed-off-by: Ian Rogers <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Oct 7, 2021
Pablo Neira Ayuso says:

====================
Netfilter fixes for net (v2)

The following patchset contains Netfilter fixes for net:

1) Move back the defrag users fields to the global netns_nf area.
   Kernel fails to boot if conntrack is builtin and kernel is booted
   with: nf_conntrack.enable_hooks=1. From Florian Westphal.

2) Rule event notification is missing relevant context such as
   the position handle and the NLM_F_APPEND flag.

3) Rule replacement is expanded to add + delete using the existing
   rule handle, reverse order of this operation so it makes sense
   from rule notification standpoint.

4) Propagate to userspace the NLM_F_CREATE and NLM_F_EXCL flags
   from the rule notification path.

Patches #2, #3 and #4 are used by 'nft monitor' and 'iptables-monitor'
userspace utilities which are not correctly representing the following
operations through netlink notifications:

- rule insertions
- rule addition/insertion from position handle
- create table/chain/set/map/flowtable/...
====================

Signed-off-by: David S. Miller <[email protected]>
heftig pushed a commit that referenced this pull request Oct 10, 2021
When passing 'phys' in the devicetree to describe the USB PHY phandle
(which is the recommended way according to
Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt) the
following NULL pointer dereference is observed on i.MX7 and i.MX8MM:

[    1.489344] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
[    1.498170] Mem abort info:
[    1.500966]   ESR = 0x96000044
[    1.504030]   EC = 0x25: DABT (current EL), IL = 32 bits
[    1.509356]   SET = 0, FnV = 0
[    1.512416]   EA = 0, S1PTW = 0
[    1.515569]   FSC = 0x04: level 0 translation fault
[    1.520458] Data abort info:
[    1.523349]   ISV = 0, ISS = 0x00000044
[    1.527196]   CM = 0, WnR = 1
[    1.530176] [0000000000000098] user address but active_mm is swapper
[    1.536544] Internal error: Oops: 96000044 [#1] PREEMPT SMP
[    1.542125] Modules linked in:
[    1.545190] CPU: 3 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-dirty #3
[    1.551901] Hardware name: Kontron i.MX8MM N801X S (DT)
[    1.557133] Workqueue: events_unbound deferred_probe_work_func
[    1.562984] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--)
[    1.568998] pc : imx7d_charger_detection+0x3f0/0x510
[    1.573973] lr : imx7d_charger_detection+0x22c/0x510

This happens because the charger functions check for the phy presence
inside the imx_usbmisc_data structure (data->usb_phy), but the chipidea
core populates the usb_phy passed via 'phys' inside 'struct ci_hdrc'
(ci->usb_phy) instead.

This causes the NULL pointer dereference inside imx7d_charger_detection().

Fix it by also searching for 'phys' in case 'fsl,usbphy' is not found.

Tested on a imx7s-warp board.

Fixes: 746f316 ("usb: chipidea: introduce imx7d USB charger detection")
Cc: [email protected]
Reported-by: Heiko Thiery <[email protected]>
Tested-by: Frieder Schrempf <[email protected]>
Reviewed-by: Frieder Schrempf <[email protected]>
Acked-by: Peter Chen <[email protected]>
Signed-off-by: Fabio Estevam <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
heftig pushed a commit that referenced this pull request Oct 27, 2021
…rbage value

Currently, when the rule related to IDLETIMER is added, idletimer_tg timer
structure is initialized by kmalloc on executing idletimer_tg_create
function. However, in this process timer->timer_type is not defined to
a specific value. Thus, timer->timer_type has garbage value and it occurs
kernel panic. So, this commit fixes the panic by initializing
timer->timer_type using kzalloc instead of kmalloc.

Test commands:
    # iptables -A OUTPUT -j IDLETIMER --timeout 1 --label test
    $ cat /sys/class/xt_idletimer/timers/test
      Killed

Splat looks like:
    BUG: KASAN: user-memory-access in alarm_expires_remaining+0x49/0x70
    Read of size 8 at addr 0000002e8c7bc4c8 by task cat/917
    CPU: 12 PID: 917 Comm: cat Not tainted 5.14.0+ #3 79940a339f71eb14fc81aee1757a20d5bf13eb0e
    Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
    Call Trace:
     dump_stack_lvl+0x6e/0x9c
     kasan_report.cold+0x112/0x117
     ? alarm_expires_remaining+0x49/0x70
     __asan_load8+0x86/0xb0
     alarm_expires_remaining+0x49/0x70
     idletimer_tg_show+0xe5/0x19b [xt_IDLETIMER 11219304af9316a21bee5ba9d58f76a6b9bccc6d]
     dev_attr_show+0x3c/0x60
     sysfs_kf_seq_show+0x11d/0x1f0
     ? device_remove_bin_file+0x20/0x20
     kernfs_seq_show+0xa4/0xb0
     seq_read_iter+0x29c/0x750
     kernfs_fop_read_iter+0x25a/0x2c0
     ? __fsnotify_parent+0x3d1/0x570
     ? iov_iter_init+0x70/0x90
     new_sync_read+0x2a7/0x3d0
     ? __x64_sys_llseek+0x230/0x230
     ? rw_verify_area+0x81/0x150
     vfs_read+0x17b/0x240
     ksys_read+0xd9/0x180
     ? vfs_write+0x460/0x460
     ? do_syscall_64+0x16/0xc0
     ? lockdep_hardirqs_on+0x79/0x120
     __x64_sys_read+0x43/0x50
     do_syscall_64+0x3b/0xc0
     entry_SYSCALL_64_after_hwframe+0x44/0xae
    RIP: 0033:0x7f0cdc819142
    Code: c0 e9 c2 fe ff ff 50 48 8d 3d 3a ca 0a 00 e8 f5 19 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
    RSP: 002b:00007fff28eee5b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
    RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f0cdc819142
    RDX: 0000000000020000 RSI: 00007f0cdc032000 RDI: 0000000000000003
    RBP: 00007f0cdc032000 R08: 00007f0cdc031010 R09: 0000000000000000
    R10: 0000000000000022 R11: 0000000000000246 R12: 00005607e9ee31f0
    R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000

Fixes: 68983a3 ("netfilter: xtables: Add snapshot of hardidletimer target")
Signed-off-by: Juhee Kang <[email protected]>
Reviewed-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
heftig pushed a commit that referenced this pull request Nov 12, 2021
Convert the 9p filesystem to use the netfs helper lib to handle readpage,
readahead and write_begin, converting those into a common issue_op for the
filesystem itself to handle.  The netfs helper lib also handles reading
from fscache if a cache is available, and interleaving reads from both
sources.

This change also switches from the old fscache I/O API to the new one,
meaning that fscache no longer keeps track of netfs pages and instead does
async DIO between the backing files and the 9p file pagecache.  As a part
of this change, the handling of PG_fscache changes.  It now just means that
the cache has a write I/O operation in progress on a page (PG_locked
is used for a read I/O op).

Note that this is a cut-down version of the fscache rewrite and does not
change any of the cookie and cache coherency handling.

Changes
=======
ver #4:
  - Rebase on top of folios.
  - Don't use wait_on_page_bit_killable().

ver #3:
  - v9fs_req_issue_op() needs to terminate the subrequest.
  - v9fs_write_end() needs to call SetPageUptodate() a bit more often.
  - It's not CONFIG_{AFS,V9FS}_FSCACHE[1]
  - v9fs_init_rreq() should take a ref on the p9_fid and the cleanup should
    drop it [from Dominique Martinet].

Signed-off-by: David Howells <[email protected]>
Reviewed-and-tested-by: Dominique Martinet <[email protected]>
cc: [email protected]
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ [1]
Link: https://lore.kernel.org/r/163162772646.438332.16323773205855053535.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/163189109885.2509237.7153668924503399173.stgit@warthog.procyon.org.uk/ # rfc v2
Link: https://lore.kernel.org/r/163363943896.1980952.1226527304649419689.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163551662876.1877519.14706391695553204156.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163584179557.4023316.11089762304657644342.stgit@warthog.procyon.org.uk # rebase on folio
Signed-off-by: Dominique Martinet <[email protected]>
heftig pushed a commit that referenced this pull request Nov 12, 2021
It is generally unsafe to call put_device() with dpm_list_mtx held,
because the given device's release routine may carry out an action
depending on that lock which then may deadlock, so modify the
system-wide suspend and resume of devices to always drop dpm_list_mtx
before calling put_device() (and adjust white space somewhat while
at it).

For instance, this prevents the following splat from showing up in
the kernel log after a system resume in certain configurations:

[ 3290.969514] ======================================================
[ 3290.969517] WARNING: possible circular locking dependency detected
[ 3290.969519] 5.15.0+ #2420 Tainted: G S
[ 3290.969523] ------------------------------------------------------
[ 3290.969525] systemd-sleep/4553 is trying to acquire lock:
[ 3290.969529] ffff888117ab1138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: flush_workqueue+0x87/0x4a0
[ 3290.969554]
               but task is already holding lock:
[ 3290.969556] ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.969571]
               which lock already depends on the new lock.

[ 3290.969573]
               the existing dependency chain (in reverse order) is:
[ 3290.969575]
               -> #3 (dpm_list_mtx){+.+.}-{3:3}:
[ 3290.969583]        __mutex_lock+0x9d/0xa30
[ 3290.969591]        device_pm_add+0x2e/0xe0
[ 3290.969597]        device_add+0x4d5/0x8f0
[ 3290.969605]        hci_conn_add_sysfs+0x43/0xb0 [bluetooth]
[ 3290.969689]        hci_conn_complete_evt.isra.71+0x124/0x750 [bluetooth]
[ 3290.969747]        hci_event_packet+0xd6c/0x28a0 [bluetooth]
[ 3290.969798]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969842]        process_one_work+0x2aa/0x650
[ 3290.969851]        worker_thread+0x39/0x400
[ 3290.969859]        kthread+0x142/0x170
[ 3290.969865]        ret_from_fork+0x22/0x30
[ 3290.969872]
               -> #2 (&hdev->lock){+.+.}-{3:3}:
[ 3290.969881]        __mutex_lock+0x9d/0xa30
[ 3290.969887]        hci_event_packet+0xba/0x28a0 [bluetooth]
[ 3290.969935]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969978]        process_one_work+0x2aa/0x650
[ 3290.969985]        worker_thread+0x39/0x400
[ 3290.969993]        kthread+0x142/0x170
[ 3290.969999]        ret_from_fork+0x22/0x30
[ 3290.970004]
               -> #1 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}:
[ 3290.970013]        process_one_work+0x27d/0x650
[ 3290.970020]        worker_thread+0x39/0x400
[ 3290.970028]        kthread+0x142/0x170
[ 3290.970033]        ret_from_fork+0x22/0x30
[ 3290.970038]
               -> #0 ((wq_completion)hci0#2){+.+.}-{0:0}:
[ 3290.970047]        __lock_acquire+0x15cb/0x1b50
[ 3290.970054]        lock_acquire+0x26c/0x300
[ 3290.970059]        flush_workqueue+0xae/0x4a0
[ 3290.970066]        drain_workqueue+0xa1/0x130
[ 3290.970073]        destroy_workqueue+0x34/0x1f0
[ 3290.970081]        hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970130]        bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970195]        device_release+0x33/0x90
[ 3290.970201]        kobject_release+0x63/0x160
[ 3290.970211]        dpm_resume+0x164/0x3e0
[ 3290.970215]        dpm_resume_end+0xd/0x20
[ 3290.970220]        suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970229]        pm_suspend+0x26b/0x310
[ 3290.970236]        state_store+0x42/0x90
[ 3290.970243]        kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970251]        new_sync_write+0x125/0x1c0
[ 3290.970257]        vfs_write+0x360/0x3c0
[ 3290.970263]        ksys_write+0xa7/0xe0
[ 3290.970269]        do_syscall_64+0x3a/0x80
[ 3290.970276]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970284]
               other info that might help us debug this:

[ 3290.970285] Chain exists of:
                 (wq_completion)hci0#2 --> &hdev->lock --> dpm_list_mtx

[ 3290.970297]  Possible unsafe locking scenario:

[ 3290.970299]        CPU0                    CPU1
[ 3290.970300]        ----                    ----
[ 3290.970302]   lock(dpm_list_mtx);
[ 3290.970306]                                lock(&hdev->lock);
[ 3290.970310]                                lock(dpm_list_mtx);
[ 3290.970314]   lock((wq_completion)hci0#2);
[ 3290.970319]
                *** DEADLOCK ***

[ 3290.970321] 7 locks held by systemd-sleep/4553:
[ 3290.970325]  #0: ffff888103bcd448 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0xa7/0xe0
[ 3290.970341]  #1: ffff888115a14488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x103/0x1b0
[ 3290.970355]  #2: ffff888100f719e0 (kn->active#233){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x10c/0x1b0
[ 3290.970369]  #3: ffffffff82661048 (autosleep_lock){+.+.}-{3:3}, at: state_store+0x12/0x90
[ 3290.970384]  #4: ffffffff82658ac8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x9f/0x310
[ 3290.970399]  #5: ffffffff827f2a48 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x4c/0x80
[ 3290.970416]  #6: ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.970428]
               stack backtrace:
[ 3290.970431] CPU: 3 PID: 4553 Comm: systemd-sleep Tainted: G S                5.15.0+ #2420
[ 3290.970438] Hardware name: Dell Inc. XPS 13 9380/0RYJWW, BIOS 1.5.0 06/03/2019
[ 3290.970441] Call Trace:
[ 3290.970446]  dump_stack_lvl+0x44/0x57
[ 3290.970454]  check_noncircular+0x105/0x120
[ 3290.970468]  ? __lock_acquire+0x15cb/0x1b50
[ 3290.970474]  __lock_acquire+0x15cb/0x1b50
[ 3290.970487]  lock_acquire+0x26c/0x300
[ 3290.970493]  ? flush_workqueue+0x87/0x4a0
[ 3290.970503]  ? __raw_spin_lock_init+0x3b/0x60
[ 3290.970510]  ? lockdep_init_map_type+0x58/0x240
[ 3290.970519]  flush_workqueue+0xae/0x4a0
[ 3290.970526]  ? flush_workqueue+0x87/0x4a0
[ 3290.970544]  ? drain_workqueue+0xa1/0x130
[ 3290.970552]  drain_workqueue+0xa1/0x130
[ 3290.970561]  destroy_workqueue+0x34/0x1f0
[ 3290.970572]  hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970624]  bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970687]  device_release+0x33/0x90
[ 3290.970695]  kobject_release+0x63/0x160
[ 3290.970705]  dpm_resume+0x164/0x3e0
[ 3290.970710]  ? dpm_resume_early+0x251/0x3b0
[ 3290.970718]  dpm_resume_end+0xd/0x20
[ 3290.970723]  suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970737]  pm_suspend+0x26b/0x310
[ 3290.970746]  state_store+0x42/0x90
[ 3290.970755]  kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970764]  new_sync_write+0x125/0x1c0
[ 3290.970777]  vfs_write+0x360/0x3c0
[ 3290.970785]  ksys_write+0xa7/0xe0
[ 3290.970794]  do_syscall_64+0x3a/0x80
[ 3290.970803]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970811] RIP: 0033:0x7f41b1328164
[ 3290.970819] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a d2 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83
[ 3290.970824] RSP: 002b:00007ffe6ae21b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 3290.970831] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f41b1328164
[ 3290.970836] RDX: 0000000000000004 RSI: 000055965e651070 RDI: 0000000000000004
[ 3290.970839] RBP: 000055965e651070 R08: 000055965e64f390 R09: 00007f41b1e3d1c0
[ 3290.970843] R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000004
[ 3290.970846] R13: 0000000000000001 R14: 000055965e64f2b0 R15: 0000000000000004

Cc: All applicable <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
heftig pushed a commit that referenced this pull request Nov 12, 2021
After removing /dev/kmem, sanitizing /proc/kcore and handling /dev/mem,
this series tackles the last sane way how a VM could accidentially
access logically unplugged memory managed by a virtio-mem device:
/proc/vmcore

When dumping memory via "makedumpfile", PG_offline pages, used by
virtio-mem to flag logically unplugged memory, are already properly
excluded; however, especially when accessing/copying /proc/vmcore "the
usual way", we can still end up reading logically unplugged memory part
of a virtio-mem device.

Patch #1-#3 are cleanups.  Patch #4 extends the existing
oldmem_pfn_is_ram mechanism.  Patch #5-#7 are virtio-mem refactorings
for patch #8, which implements the virtio-mem logic to query the state
of device blocks.

Patch #8:
 "Although virtio-mem currently supports reading unplugged memory in the
  hypervisor, this will change in the future, indicated to the device
  via a new feature flag. We similarly sanitized /proc/kcore access
  recently.
  [...]
  Distributions that support virtio-mem+kdump have to make sure that the
  virtio_mem module will be part of the kdump kernel or the kdump
  initrd; dracut was recently [2] extended to include virtio-mem in the
  generated initrd. As long as no special kdump kernels are used, this
  will automatically make sure that virtio-mem will be around in the
  kdump initrd and sanitize /proc/vmcore access -- with dracut"

This is the last remaining bit to support
VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE [3] in the Linux implementation of
virtio-mem.

Note: this is best-effort.  We'll never be able to control what runs
inside the second kernel, really, but we also don't have to care: we
only care about sane setups where we don't want our VM getting zapped
once we touch the wrong memory location while dumping.  While we usually
expect sane setups to use "makedumfile", nothing really speaks against
just copying /proc/vmcore, especially in environments where HWpoisioning
isn't typically expected.  Also, we really don't want to put all our
trust completely on the memmap, so sanitizing also makes sense when just
using "makedumpfile".

[1] https://lkml.kernel.org/r/[email protected]
[2] dracutdevs/dracut#1157
[3] https://lists.oasis-open.org/archives/virtio-comment/202109/msg00021.html

This patch (of 9):

The callback is only used for the vmcore nowadays.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
A malicious HID device can trigger a slab out-of-bounds during
mt_report_fixup() by passing in report descriptor smaller than
607 bytes. mt_report_fixup() attempts to patch byte offset 607
of the descriptor with 0x25 by first checking if byte offset
607 is 0x15 however it lacks bounds checks to verify if the
descriptor is big enough before conducting this check. Fix
this bug by ensuring the descriptor size is at least 608
bytes before accessing it.

Below is the KASAN splat after the out of bounds access happens:

[   13.671954] ==================================================================
[   13.672667] BUG: KASAN: slab-out-of-bounds in mt_report_fixup+0x103/0x110
[   13.673297] Read of size 1 at addr ffff888103df39df by task kworker/0:1/10
[   13.673297]
[   13.673297] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0-00005-gec5d573d83f4-dirty #3
[   13.673297] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/04
[   13.673297] Call Trace:
[   13.673297]  <TASK>
[   13.673297]  dump_stack_lvl+0x5f/0x80
[   13.673297]  print_report+0xd1/0x660
[   13.673297]  kasan_report+0xe5/0x120
[   13.673297]  __asan_report_load1_noabort+0x18/0x20
[   13.673297]  mt_report_fixup+0x103/0x110
[   13.673297]  hid_open_report+0x1ef/0x810
[   13.673297]  mt_probe+0x422/0x960
[   13.673297]  hid_device_probe+0x2e2/0x6f0
[   13.673297]  really_probe+0x1c6/0x6b0
[   13.673297]  __driver_probe_device+0x24f/0x310
[   13.673297]  driver_probe_device+0x4e/0x220
[   13.673297]  __device_attach_driver+0x169/0x320
[   13.673297]  bus_for_each_drv+0x11d/0x1b0
[   13.673297]  __device_attach+0x1b8/0x3e0
[   13.673297]  device_initial_probe+0x12/0x20
[   13.673297]  bus_probe_device+0x13d/0x180
[   13.673297]  device_add+0xe3a/0x1670
[   13.673297]  hid_add_device+0x31d/0xa40
[...]

Fixes: c8000de ("HID: multitouch: Add support for GT7868Q")
Cc: [email protected]
Signed-off-by: Qasim Ijaz <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
When a large VM, specifically one that holds a significant number of PTEs,
gets abruptly destroyed, the following warning is seen during the
page-table walk:

 sched: CPU 0 need_resched set for > 100018840 ns (100 ticks) without schedule
 CPU: 0 UID: 0 PID: 9617 Comm: kvm_page_table_ Tainted: G O 6.16.0-smp-DEV #3 NONE
 Tainted: [O]=OOT_MODULE
 Call trace:
  show_stack+0x20/0x38 (C)
  dump_stack_lvl+0x3c/0xb8
  dump_stack+0x18/0x30
  resched_latency_warn+0x7c/0x88
  sched_tick+0x1c4/0x268
  update_process_times+0xa8/0xd8
  tick_nohz_handler+0xc8/0x168
  __hrtimer_run_queues+0x11c/0x338
  hrtimer_interrupt+0x104/0x308
  arch_timer_handler_phys+0x40/0x58
  handle_percpu_devid_irq+0x8c/0x1b0
  generic_handle_domain_irq+0x48/0x78
  gic_handle_irq+0x1b8/0x408
  call_on_irq_stack+0x24/0x30
  do_interrupt_handler+0x54/0x78
  el1_interrupt+0x44/0x88
  el1h_64_irq_handler+0x18/0x28
  el1h_64_irq+0x84/0x88
  stage2_free_walker+0x30/0xa0 (P)
  __kvm_pgtable_walk+0x11c/0x258
  __kvm_pgtable_walk+0x180/0x258
  __kvm_pgtable_walk+0x180/0x258
  __kvm_pgtable_walk+0x180/0x258
  kvm_pgtable_walk+0xc4/0x140
  kvm_pgtable_stage2_destroy+0x5c/0xf0
  kvm_free_stage2_pgd+0x6c/0xe8
  kvm_uninit_stage2_mmu+0x24/0x48
  kvm_arch_flush_shadow_all+0x80/0xa0
  kvm_mmu_notifier_release+0x38/0x78
  __mmu_notifier_release+0x15c/0x250
  exit_mmap+0x68/0x400
  __mmput+0x38/0x1c8
  mmput+0x30/0x68
  exit_mm+0xd4/0x198
  do_exit+0x1a4/0xb00
  do_group_exit+0x8c/0x120
  get_signal+0x6d4/0x778
  do_signal+0x90/0x718
  do_notify_resume+0x70/0x170
  el0_svc+0x74/0xd8
  el0t_64_sync_handler+0x60/0xc8
  el0t_64_sync+0x1b0/0x1b8

The warning is seen majorly on the host kernels that are configured
not to force-preempt, such as CONFIG_PREEMPT_NONE=y. To avoid this,
instead of walking the entire page-table in one go, split it into
smaller ranges, by checking for cond_resched() between each range.
Since the path is executed during VM destruction, after the
page-table structure is unlinked from the KVM MMU, relying on
cond_resched_rwlock_write() isn't necessary.

Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Suggested-by: Oliver Upton <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Oliver Upton <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
These iterations require the read lock, otherwise RCU
lockdep will splat:

=============================
WARNING: suspicious RCU usage
6.17.0-rc3-00014-g31419c045d64 #6 Tainted: G           O
-----------------------------
drivers/base/power/main.c:1333 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
5 locks held by rtcwake/547:
 #0: 00000000643ab418 (sb_writers#6){.+.+}-{0:0}, at: file_start_write+0x2b/0x3a
 #1: 0000000067a0ca88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x181/0x24b
 #2: 00000000631eac40 (kn->active#3){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x191/0x24b
 #3: 00000000609a1308 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0xaf/0x30b
 #4: 0000000060c0fdb0 (device_links_srcu){.+.+}-{0:0}, at: device_links_read_lock+0x75/0x98

stack backtrace:
CPU: 0 UID: 0 PID: 547 Comm: rtcwake Tainted: G           O        6.17.0-rc3-00014-g31419c045d64 #6 VOLUNTARY
Tainted: [O]=OOT_MODULE
Stack:
 223721b3a80 6089eac6 00000001 00000001
 ffffff00 6089eac6 00000535 6086e528
 721b3ac0 6003c294 00000000 60031fc0
Call Trace:
 [<600407ed>] show_stack+0x10e/0x127
 [<6003c294>] dump_stack_lvl+0x77/0xc6
 [<6003c2fd>] dump_stack+0x1a/0x20
 [<600bc2f8>] lockdep_rcu_suspicious+0x116/0x13e
 [<603d8ea1>] dpm_async_suspend_superior+0x117/0x17e
 [<603d980f>] device_suspend+0x528/0x541
 [<603da24b>] dpm_suspend+0x1a2/0x267
 [<603da837>] dpm_suspend_start+0x5d/0x72
 [<600ca0c9>] suspend_devices_and_enter+0xab/0x736
 [...]

Add the fourth argument to the iteration to annotate
this and avoid the splat.

Fixes: 0679963 ("PM: sleep: Make async suspend handle suppliers like parents")
Fixes: ed18738 ("PM: sleep: Make async resume handle consumers like children")
Signed-off-by: Johannes Berg <[email protected]>
Link: https://patch.msgid.link/20250826134348.aba79f6e6299.I9ecf55da46ccf33778f2c018a82e1819d815b348@changeid
Signed-off-by: Rafael J. Wysocki <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
When the "proxy" option is enabled on a VXLAN device, the device will
suppress ARP requests and IPv6 Neighbor Solicitation messages if it is
able to reply on behalf of the remote host. That is, if a matching and
valid neighbor entry is configured on the VXLAN device whose MAC address
is not behind the "any" remote (0.0.0.0 / ::).

The code currently assumes that the FDB entry for the neighbor's MAC
address points to a valid remote destination, but this is incorrect if
the entry is associated with an FDB nexthop group. This can result in a
NPD [1][3] which can be reproduced using [2][4].

Fix by checking that the remote destination exists before dereferencing
it.

[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
CPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
RIP: 0010:vxlan_xmit+0xb58/0x15f0
[...]
Call Trace:
 <TASK>
 dev_hard_start_xmit+0x5d/0x1c0
 __dev_queue_xmit+0x246/0xfd0
 packet_sendmsg+0x113a/0x1850
 __sock_sendmsg+0x38/0x70
 __sys_sendto+0x126/0x180
 __x64_sys_sendto+0x24/0x30
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

[2]
 #!/bin/bash

 ip address add 192.0.2.1/32 dev lo

 ip nexthop add id 1 via 192.0.2.2 fdb
 ip nexthop add id 10 group 1 fdb

 ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy

 ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0

 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10

 arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3

[3]
BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
CPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014
RIP: 0010:vxlan_xmit+0x803/0x1600
[...]
Call Trace:
 <TASK>
 dev_hard_start_xmit+0x5d/0x1c0
 __dev_queue_xmit+0x246/0xfd0
 ip6_finish_output2+0x210/0x6c0
 ip6_finish_output+0x1af/0x2b0
 ip6_mr_output+0x92/0x3e0
 ip6_send_skb+0x30/0x90
 rawv6_sendmsg+0xe6e/0x12e0
 __sock_sendmsg+0x38/0x70
 __sys_sendto+0x126/0x180
 __x64_sys_sendto+0x24/0x30
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f383422ec77

[4]
 #!/bin/bash

 ip address add 2001:db8:1::1/128 dev lo

 ip nexthop add id 1 via 2001:db8:1::1 fdb
 ip nexthop add id 10 group 1 fdb

 ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy

 ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0

 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10

 ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0

Fixes: 1274e1c ("vxlan: ecmp support for mac fdb entries")
Reviewed-by: Petr Machata <[email protected]>
Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
Ido Schimmel says:

====================
vxlan: Fix NPDs when using nexthop objects

With FDB nexthop groups, VXLAN FDB entries do not necessarily point to
a remote destination but rather to an FDB nexthop group. This means that
first_remote_{rcu,rtnl}() can return NULL and a few places in the driver
were not ready for that, resulting in NULL pointer dereferences.
Patches #1-#2 fix these NPDs.

Note that vxlan_fdb_find_uc() still dereferences the remote returned by
first_remote_rcu() without checking that it is not NULL, but this
function is only invoked by a single driver which vetoes the creation of
FDB nexthop groups. I will patch this in net-next to make the code less
fragile.

Patch #3 adds a selftests which exercises these code paths and tests
basic Tx functionality with FDB nexthop groups. I verified that the test
crashes the kernel without the first two patches.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
When transmitting a PTP frame which is timestamp using 2 step, the
following warning appears if CONFIG_PROVE_LOCKING is enabled:
=============================
[ BUG: Invalid wait context ]
6.17.0-rc1-00326-ge6160462704e torvalds#427 Not tainted
-----------------------------
ptp4l/119 is trying to lock:
c2a44ed4 (&vsc8531->ts_lock){+.+.}-{3:3}, at: vsc85xx_txtstamp+0x50/0xac
other info that might help us debug this:
context-{4:4}
4 locks held by ptp4l/119:
 #0: c145f068 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x58/0x1440
 #1: c29df974 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x5c4/0x1440
 #2: c2aaaad0 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x108/0x350
 #3: c2aac170 (&lan966x->tx_lock){+.-.}-{2:2}, at: lan966x_port_xmit+0xd0/0x350
stack backtrace:
CPU: 0 UID: 0 PID: 119 Comm: ptp4l Not tainted 6.17.0-rc1-00326-ge6160462704e torvalds#427 NONE
Hardware name: Generic DT based system
Call trace:
 unwind_backtrace from show_stack+0x10/0x14
 show_stack from dump_stack_lvl+0x7c/0xac
 dump_stack_lvl from __lock_acquire+0x8e8/0x29dc
 __lock_acquire from lock_acquire+0x108/0x38c
 lock_acquire from __mutex_lock+0xb0/0xe78
 __mutex_lock from mutex_lock_nested+0x1c/0x24
 mutex_lock_nested from vsc85xx_txtstamp+0x50/0xac
 vsc85xx_txtstamp from lan966x_fdma_xmit+0xd8/0x3a8
 lan966x_fdma_xmit from lan966x_port_xmit+0x1bc/0x350
 lan966x_port_xmit from dev_hard_start_xmit+0xc8/0x2c0
 dev_hard_start_xmit from sch_direct_xmit+0x8c/0x350
 sch_direct_xmit from __dev_queue_xmit+0x680/0x1440
 __dev_queue_xmit from packet_sendmsg+0xfa4/0x1568
 packet_sendmsg from __sys_sendto+0x110/0x19c
 __sys_sendto from sys_send+0x18/0x20
 sys_send from ret_fast_syscall+0x0/0x1c
Exception stack(0xf0b05fa8 to 0xf0b05ff0)
5fa0:                   00000001 0000000 0000000 0004b47a 0000003a 00000000
5fc0: 00000001 0000000 00000000 00000121 0004af58 00044874 00000000 00000000
5fe0: 00000001 bee9d420 00025a10 b6e75c7c

So, instead of using the ts_lock for tx_queue, use the spinlock that
skb_buff_head has.

Reviewed-by: Vadim Fedorenko <[email protected]>
Fixes: 7d272e6 ("net: phy: mscc: timestamping and PHC support")
Signed-off-by: Horatiu Vultur <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
[ Upstream commit 1db9df8 ]

The QuickI2C ACPI _DSD methods return ICRS and ISUB data with a
trailing byte, making the actual length is one more byte than the
structs defined.

It caused stack-out-of-bounds and kernel crash:

kernel: BUG: KASAN: stack-out-of-bounds in quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel: Write of size 12 at addr ffff888106d1f900 by task kworker/u33:2/75
kernel:
kernel: CPU: 3 UID: 0 PID: 75 Comm: kworker/u33:2 Not tainted 6.16.0+ #3 PREEMPT(voluntary)
kernel: Workqueue: async async_run_entry_fn
kernel: Call Trace:
kernel:  <TASK>
kernel:  dump_stack_lvl+0x76/0xa0
kernel:  print_report+0xd1/0x660
kernel:  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
kernel:  ? __kasan_slab_free+0x5d/0x80
kernel:  ? kasan_addr_to_slab+0xd/0xb0
kernel:  kasan_report+0xe1/0x120
kernel:  ? quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  ? quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  kasan_check_range+0x11c/0x200
kernel:  __asan_memcpy+0x3b/0x80
kernel:  quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  ? __pfx_quicki2c_acpi_get_dsd_property.constprop.0+0x10/0x10 [intel_quicki2c]
kernel:  quicki2c_get_acpi_resources+0x237/0x730 [intel_quicki2c]
[...]
kernel:  </TASK>
kernel:
kernel: The buggy address belongs to stack of task kworker/u33:2/75
kernel:  and is located at offset 48 in frame:
kernel:  quicki2c_get_acpi_resources+0x0/0x730 [intel_quicki2c]
kernel:
kernel: This frame has 3 objects:
kernel:  [32, 36) 'hid_desc_addr'
kernel:  [48, 59) 'i2c_param'
kernel:  [80, 224) 'i2c_config'

ACPI DSD methods return:

\_SB.PC00.THC0.ICRS Buffer       000000003fdc947b 001 Len 0C = 0A 00 80 1A 06 00 00 00 00 00 00 00
\_SB.PC00.THC0.ISUB Buffer       00000000f2fcbdc4 001 Len 91 = 00 00 00 00 00 00 00 00 00 00 00 00

Adding reserved padding to quicki2c_subip_acpi_parameter/config.

Fixes: 5282e45 ("HID: intel-thc-hid: intel-quicki2c: Add THC QuickI2C ACPI interfaces")
Signed-off-by: Aaron Ma <[email protected]>
Reviewed-by: Even Xu <[email protected]>
Tested-by: Even Xu <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
…C regs save

[ Upstream commit a7fc15e ]

Improper use of secondary pointer (&dev->i2c_subip_regs) caused
kernel crash and out-of-bounds error:

 BUG: KASAN: slab-out-of-bounds in _regmap_bulk_read+0x449/0x510
 Write of size 4 at addr ffff888136005dc0 by task kworker/u33:5/5107

 CPU: 3 UID: 0 PID: 5107 Comm: kworker/u33:5 Not tainted 6.16.0+ #3 PREEMPT(voluntary)
 Workqueue: async async_run_entry_fn
 Call Trace:
  <TASK>
  dump_stack_lvl+0x76/0xa0
  print_report+0xd1/0x660
  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
  ? kasan_complete_mode_report_info+0x26/0x200
  kasan_report+0xe1/0x120
  ? _regmap_bulk_read+0x449/0x510
  ? _regmap_bulk_read+0x449/0x510
  __asan_report_store4_noabort+0x17/0x30
  _regmap_bulk_read+0x449/0x510
  ? __pfx__regmap_bulk_read+0x10/0x10
  regmap_bulk_read+0x270/0x3d0
  pio_complete+0x1ee/0x2c0 [intel_thc]
  ? __pfx_pio_complete+0x10/0x10 [intel_thc]
  ? __pfx_pio_wait+0x10/0x10 [intel_thc]
  ? regmap_update_bits_base+0x13b/0x1f0
  thc_i2c_subip_pio_read+0x117/0x270 [intel_thc]
  thc_i2c_subip_regs_save+0xc2/0x140 [intel_thc]
  ? __pfx_thc_i2c_subip_regs_save+0x10/0x10 [intel_thc]
[...]
 The buggy address belongs to the object at ffff888136005d00
  which belongs to the cache kmalloc-rnd-12-192 of size 192
 The buggy address is located 0 bytes to the right of
  allocated 192-byte region [ffff888136005d00, ffff888136005dc0)

Replaced with direct array indexing (&dev->i2c_subip_regs[i]) to ensure
safe memory access.

Fixes: 4228966 ("HID: intel-thc-hid: intel-thc: Add THC I2C config interfaces")
Signed-off-by: Aaron Ma <[email protected]>
Reviewed-by: Even Xu <[email protected]>
Tested-by: Even Xu <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Sep 4, 2025
commit 0379eb8 upstream.

A malicious HID device can trigger a slab out-of-bounds during
mt_report_fixup() by passing in report descriptor smaller than
607 bytes. mt_report_fixup() attempts to patch byte offset 607
of the descriptor with 0x25 by first checking if byte offset
607 is 0x15 however it lacks bounds checks to verify if the
descriptor is big enough before conducting this check. Fix
this bug by ensuring the descriptor size is at least 608
bytes before accessing it.

Below is the KASAN splat after the out of bounds access happens:

[   13.671954] ==================================================================
[   13.672667] BUG: KASAN: slab-out-of-bounds in mt_report_fixup+0x103/0x110
[   13.673297] Read of size 1 at addr ffff888103df39df by task kworker/0:1/10
[   13.673297]
[   13.673297] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0-00005-gec5d573d83f4-dirty #3
[   13.673297] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/04
[   13.673297] Call Trace:
[   13.673297]  <TASK>
[   13.673297]  dump_stack_lvl+0x5f/0x80
[   13.673297]  print_report+0xd1/0x660
[   13.673297]  kasan_report+0xe5/0x120
[   13.673297]  __asan_report_load1_noabort+0x18/0x20
[   13.673297]  mt_report_fixup+0x103/0x110
[   13.673297]  hid_open_report+0x1ef/0x810
[   13.673297]  mt_probe+0x422/0x960
[   13.673297]  hid_device_probe+0x2e2/0x6f0
[   13.673297]  really_probe+0x1c6/0x6b0
[   13.673297]  __driver_probe_device+0x24f/0x310
[   13.673297]  driver_probe_device+0x4e/0x220
[   13.673297]  __device_attach_driver+0x169/0x320
[   13.673297]  bus_for_each_drv+0x11d/0x1b0
[   13.673297]  __device_attach+0x1b8/0x3e0
[   13.673297]  device_initial_probe+0x12/0x20
[   13.673297]  bus_probe_device+0x13d/0x180
[   13.673297]  device_add+0xe3a/0x1670
[   13.673297]  hid_add_device+0x31d/0xa40
[...]

Fixes: c8000de ("HID: multitouch: Add support for GT7868Q")
Cc: [email protected]
Signed-off-by: Qasim Ijaz <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
heftig pushed a commit that referenced this pull request Sep 10, 2025
[ Upstream commit 1f5d2fd ]

When the "proxy" option is enabled on a VXLAN device, the device will
suppress ARP requests and IPv6 Neighbor Solicitation messages if it is
able to reply on behalf of the remote host. That is, if a matching and
valid neighbor entry is configured on the VXLAN device whose MAC address
is not behind the "any" remote (0.0.0.0 / ::).

The code currently assumes that the FDB entry for the neighbor's MAC
address points to a valid remote destination, but this is incorrect if
the entry is associated with an FDB nexthop group. This can result in a
NPD [1][3] which can be reproduced using [2][4].

Fix by checking that the remote destination exists before dereferencing
it.

[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
CPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
RIP: 0010:vxlan_xmit+0xb58/0x15f0
[...]
Call Trace:
 <TASK>
 dev_hard_start_xmit+0x5d/0x1c0
 __dev_queue_xmit+0x246/0xfd0
 packet_sendmsg+0x113a/0x1850
 __sock_sendmsg+0x38/0x70
 __sys_sendto+0x126/0x180
 __x64_sys_sendto+0x24/0x30
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

[2]
 #!/bin/bash

 ip address add 192.0.2.1/32 dev lo

 ip nexthop add id 1 via 192.0.2.2 fdb
 ip nexthop add id 10 group 1 fdb

 ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy

 ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0

 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10

 arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3

[3]
BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
CPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014
RIP: 0010:vxlan_xmit+0x803/0x1600
[...]
Call Trace:
 <TASK>
 dev_hard_start_xmit+0x5d/0x1c0
 __dev_queue_xmit+0x246/0xfd0
 ip6_finish_output2+0x210/0x6c0
 ip6_finish_output+0x1af/0x2b0
 ip6_mr_output+0x92/0x3e0
 ip6_send_skb+0x30/0x90
 rawv6_sendmsg+0xe6e/0x12e0
 __sock_sendmsg+0x38/0x70
 __sys_sendto+0x126/0x180
 __x64_sys_sendto+0x24/0x30
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f383422ec77

[4]
 #!/bin/bash

 ip address add 2001:db8:1::1/128 dev lo

 ip nexthop add id 1 via 2001:db8:1::1 fdb
 ip nexthop add id 10 group 1 fdb

 ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy

 ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0

 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10

 ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0

Fixes: 1274e1c ("vxlan: ecmp support for mac fdb entries")
Reviewed-by: Petr Machata <[email protected]>
Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Sep 10, 2025
[ Upstream commit 9b2bfdb ]

When transmitting a PTP frame which is timestamp using 2 step, the
following warning appears if CONFIG_PROVE_LOCKING is enabled:
=============================
[ BUG: Invalid wait context ]
6.17.0-rc1-00326-ge6160462704e torvalds#427 Not tainted
-----------------------------
ptp4l/119 is trying to lock:
c2a44ed4 (&vsc8531->ts_lock){+.+.}-{3:3}, at: vsc85xx_txtstamp+0x50/0xac
other info that might help us debug this:
context-{4:4}
4 locks held by ptp4l/119:
 #0: c145f068 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x58/0x1440
 #1: c29df974 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x5c4/0x1440
 #2: c2aaaad0 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x108/0x350
 #3: c2aac170 (&lan966x->tx_lock){+.-.}-{2:2}, at: lan966x_port_xmit+0xd0/0x350
stack backtrace:
CPU: 0 UID: 0 PID: 119 Comm: ptp4l Not tainted 6.17.0-rc1-00326-ge6160462704e torvalds#427 NONE
Hardware name: Generic DT based system
Call trace:
 unwind_backtrace from show_stack+0x10/0x14
 show_stack from dump_stack_lvl+0x7c/0xac
 dump_stack_lvl from __lock_acquire+0x8e8/0x29dc
 __lock_acquire from lock_acquire+0x108/0x38c
 lock_acquire from __mutex_lock+0xb0/0xe78
 __mutex_lock from mutex_lock_nested+0x1c/0x24
 mutex_lock_nested from vsc85xx_txtstamp+0x50/0xac
 vsc85xx_txtstamp from lan966x_fdma_xmit+0xd8/0x3a8
 lan966x_fdma_xmit from lan966x_port_xmit+0x1bc/0x350
 lan966x_port_xmit from dev_hard_start_xmit+0xc8/0x2c0
 dev_hard_start_xmit from sch_direct_xmit+0x8c/0x350
 sch_direct_xmit from __dev_queue_xmit+0x680/0x1440
 __dev_queue_xmit from packet_sendmsg+0xfa4/0x1568
 packet_sendmsg from __sys_sendto+0x110/0x19c
 __sys_sendto from sys_send+0x18/0x20
 sys_send from ret_fast_syscall+0x0/0x1c
Exception stack(0xf0b05fa8 to 0xf0b05ff0)
5fa0:                   00000001 0000000 0000000 0004b47a 0000003a 00000000
5fc0: 00000001 0000000 00000000 00000121 0004af58 00044874 00000000 00000000
5fe0: 00000001 bee9d420 00025a10 b6e75c7c

So, instead of using the ts_lock for tx_queue, use the spinlock that
skb_buff_head has.

Reviewed-by: Vadim Fedorenko <[email protected]>
Fixes: 7d272e6 ("net: phy: mscc: timestamping and PHC support")
Signed-off-by: Horatiu Vultur <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Sep 19, 2025
Problem description
===================

Lockdep reports a possible circular locking dependency (AB/BA) between
&pl->state_mutex and &phy->lock, as follows.

phylink_resolve() // acquires &pl->state_mutex
-> phylink_major_config()
   -> phy_config_inband() // acquires &pl->phydev->lock

whereas all the other call sites where &pl->state_mutex and
&pl->phydev->lock have the locking scheme reversed. Everywhere else,
&pl->phydev->lock is acquired at the top level, and &pl->state_mutex at
the lower level. A clear example is phylink_bringup_phy().

The outlier is the newly introduced phy_config_inband() and the existing
lock order is the correct one. To understand why it cannot be the other
way around, it is sufficient to consider phylink_phy_change(), phylink's
callback from the PHY device's phy->phy_link_change() virtual method,
invoked by the PHY state machine.

phy_link_up() and phy_link_down(), the (indirect) callers of
phylink_phy_change(), are called with &phydev->lock acquired.
Then phylink_phy_change() acquires its own &pl->state_mutex, to
serialize changes made to its pl->phy_state and pl->link_config.
So all other instances of &pl->state_mutex and &phydev->lock must be
consistent with this order.

Problem impact
==============

I think the kernel runs a serious deadlock risk if an existing
phylink_resolve() thread, which results in a phy_config_inband() call,
is concurrent with a phy_link_up() or phy_link_down() call, which will
deadlock on &pl->state_mutex in phylink_phy_change(). Practically
speaking, the impact may be limited by the slow speed of the medium
auto-negotiation protocol, which makes it unlikely for the current state
to still be unresolved when a new one is detected, but I think the
problem is there. Nonetheless, the problem was discovered using lockdep.

Proposed solution
=================

Practically speaking, the phy_config_inband() requirement of having
phydev->lock acquired must transfer to the caller (phylink is the only
caller). There, it must bubble up until immediately before
&pl->state_mutex is acquired, for the cases where that takes place.

Solution details, considerations, notes
=======================================

This is the phy_config_inband() call graph:

                          sfp_upstream_ops :: connect_phy()
                          |
                          v
                          phylink_sfp_connect_phy()
                          |
                          v
                          phylink_sfp_config_phy()
                          |
                          |   sfp_upstream_ops :: module_insert()
                          |   |
                          |   v
                          |   phylink_sfp_module_insert()
                          |   |
                          |   |   sfp_upstream_ops :: module_start()
                          |   |   |
                          |   |   v
                          |   |   phylink_sfp_module_start()
                          |   |   |
                          |   v   v
                          |   phylink_sfp_config_optical()
 phylink_start()          |   |
   |   phylink_resume()   v   v
   |   |  phylink_sfp_set_config()
   |   |  |
   v   v  v
 phylink_mac_initial_config()
   |   phylink_resolve()
   |   |  phylink_ethtool_ksettings_set()
   v   v  v
   phylink_major_config()
            |
            v
    phy_config_inband()

phylink_major_config() caller #1, phylink_mac_initial_config(), does not
acquire &pl->state_mutex nor do its callers. It must acquire
&pl->phydev->lock prior to calling phylink_major_config().

phylink_major_config() caller #2, phylink_resolve() acquires
&pl->state_mutex, thus also needs to acquire &pl->phydev->lock.

phylink_major_config() caller #3, phylink_ethtool_ksettings_set(), is
completely uninteresting, because it only calls phylink_major_config()
if pl->phydev is NULL (otherwise it calls phy_ethtool_ksettings_set()).
We need to change nothing there.

Other solutions
===============

The lock inversion between &pl->state_mutex and &pl->phydev->lock has
occurred at least once before, as seen in commit c718af2 ("net:
phylink: fix ethtool -A with attached PHYs"). The solution there was to
simply not call phy_set_asym_pause() under the &pl->state_mutex. That
cannot be extended to our case though, where the phy_config_inband()
call is much deeper inside the &pl->state_mutex section.

Fixes: 5fd0f1a ("net: phylink: add negotiation of in-band capabilities")
Signed-off-by: Vladimir Oltean <[email protected]>
Reviewed-by: Russell King (Oracle) <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Sep 19, 2025
…ux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 changes for 6.17, round #3

 - Invalidate nested MMUs upon freeing the PGD to avoid WARNs when
   visiting from an MMU notifier

 - Fixes to the TLB match process and TLB invalidation range for
   managing the VCNR pseudo-TLB

 - Prevent SPE from erroneously profiling guests due to UNKNOWN reset
   values in PMSCR_EL1

 - Fix save/restore of host MDCR_EL2 to account for eagerly programming
   at vcpu_load() on VHE systems

 - Correct lock ordering when dealing with VGIC LPIs, avoiding scenarios
   where an xarray's spinlock was nested with a *raw* spinlock

 - Permit stage-2 read permission aborts which are possible in the case
   of NV depending on the guest hypervisor's stage-2 translation

 - Call raw_spin_unlock() instead of the internal spinlock API

 - Fix parameter ordering when assigning VBAR_EL1
heftig pushed a commit that referenced this pull request Sep 25, 2025
This fixes the following UAF caused by not properly locking hdev when
processing HCI_EV_NUM_COMP_PKTS:

BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036
Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54

CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted 6.16.0-rc7 #3 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036
 hci_num_comp_pkts_evt+0x1c8/0xa50 net/bluetooth/hci_event.c:4404
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 54:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 le_conn_complete_evt+0x3d6/0x1220 net/bluetooth/hci_event.c:5628
 hci_le_enh_conn_complete_evt+0x189/0x470 net/bluetooth/hci_event.c:5794
 hci_event_func net/bluetooth/hci_event.c:7474 [inline]
 hci_event_packet+0x78c/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Freed by task 9572:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_abort_conn_sync+0x5d1/0xdf0 net/bluetooth/hci_sync.c:5689
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Fixes: 134f4b3 ("Bluetooth: add support for skb TX SND/COMPLETION timestamping")
Reported-by: Junvyyang, Tencent Zhuque Lab <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
heftig pushed a commit that referenced this pull request Sep 25, 2025
This fixes the following UFA in hci_acl_create_conn_sync where a
connection still pending is command submission (conn->state == BT_OPEN)
maybe freed, also since this also can happen with the likes of
hci_le_create_conn_sync fix it as well:

BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
Write of size 2 at addr ffff88805ffcc038 by task kworker/u11:2/9541

CPU: 1 UID: 0 PID: 9541 Comm: kworker/u11:2 Not tainted 6.16.0-rc7 #3 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci3 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 123736:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 hci_conn_add_unset net/bluetooth/hci_conn.c:1051 [inline]
 hci_connect_acl+0x16c/0x4e0 net/bluetooth/hci_conn.c:1634
 pair_device+0x418/0xa70 net/bluetooth/mgmt.c:3556
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 sock_write_iter+0x258/0x330 net/socket.c:1131
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x54b/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 103680:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 insert_work+0x3d/0x330 kernel/workqueue.c:2183
 __queue_work+0xbd9/0xfe0 kernel/workqueue.c:2345
 queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561
 pairing_complete+0x1e7/0x2b0 net/bluetooth/mgmt.c:3451
 pairing_complete_cb+0x1ac/0x230 net/bluetooth/mgmt.c:3487
 hci_connect_cfm include/net/bluetooth/hci_core.h:2064 [inline]
 hci_conn_failed+0x24d/0x310 net/bluetooth/hci_conn.c:1275
 hci_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Fixes: aef2aa4 ("Bluetooth: hci_event: Fix creating hci_conn object on error status")
Reported-by: Junvyyang, Tencent Zhuque Lab <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
heftig pushed a commit that referenced this pull request Sep 25, 2025
Ido Schimmel says:

====================
nexthop: Various fixes

Patch #1 fixes a NPD that was recently reported by syzbot.

Patch #2 fixes an issue in the existing FIB nexthop selftest.

Patch #3 extends the selftest with test cases for the bug that was fixed
in the first patch.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Oct 12, 2025
The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    torvalds#10 0x565358f682bd in cmd_test builtin-test.c:849
    torvalds#11 0x565358ee5ded in run_builtin perf.c:349
    torvalds#12 0x565358ee6085 in handle_internal_command perf.c:401
    torvalds#13 0x565358ee61de in run_argv perf.c:448
    torvalds#14 0x565358ee6527 in main perf.c:555
    torvalds#15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    torvalds#16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    torvalds#17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
heftig pushed a commit that referenced this pull request Oct 12, 2025
Don't emulate branch instructions, e.g. CALL/RET/JMP etc., that are
affected by Shadow Stacks and/or Indirect Branch Tracking when said
features are enabled in the guest, as fully emulating CET would require
significant complexity for no practical benefit (KVM shouldn't need to
emulate branch instructions on modern hosts).  Simply doing nothing isn't
an option as that would allow a malicious entity to subvert CET
protections via the emulator.

To detect instructions that are subject to IBT or affect IBT state, use
the existing IsBranch flag along with the source operand type to detect
indirect branches, and the existing NearBranch flag to detect far JMPs
and CALLs, all of which are effectively indirect.  Explicitly check for
emulation of IRET, FAR RET (IMM), and SYSEXIT (the ret-like far branches)
instead of adding another flag, e.g. IsRet, as it's unlikely the emulator
will ever need to check for return-like instructions outside of this one
specific flow.  Use an allow-list instead of a deny-list because (a) it's
a shorter list and (b) so that a missed entry gets a false positive, not a
false negative (i.e. reject emulation instead of clobbering CET state).

For Shadow Stacks, explicitly track instructions that directly affect the
current SSP, as KVM's emulator doesn't have existing flags that can be
used to precisely detect such instructions.  Alternatively, the em_xxx()
helpers could directly check for ShadowStack interactions, but using a
dedicated flag is arguably easier to audit, and allows for handling both
IBT and SHSTK in one fell swoop.

Note!  On far transfers, do NOT consult the current privilege level and
instead treat SHSTK/IBT as being enabled if they're enabled for User *or*
Supervisor mode.  On inter-privilege level far transfers, SHSTK and IBT
can be in play for the target privilege level, i.e. checking the current
privilege could get a false negative, and KVM doesn't know the target
privilege level until emulation gets under way.

Note #2, FAR JMP from 64-bit mode to compatibility mode interacts with
the current SSP, but only to ensure SSP[63:32] == 0.  Don't tag FAR JMP
as SHSTK, which would be rather confusing and would result in FAR JMP
being rejected unnecessarily the vast majority of the time (ignoring that
it's unlikely to ever be emulated).  A future commit will add the #GP(0)
check for the specific FAR JMP scenario.

Note #3, task switches also modify SSP and so need to be rejected.  That
too will be addressed in a future commit.

Suggested-by: Chao Gao <[email protected]>
Originally-by: Yang Weijiang <[email protected]>
Cc: Mathias Krause <[email protected]>
Cc: John Allen <[email protected]>
Cc: Rick Edgecombe <[email protected]>
Reviewed-by: Chao Gao <[email protected]>
Reviewed-by: Binbin Wu <[email protected]>
Reviewed-by: Xiaoyao Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>
heftig pushed a commit that referenced this pull request Oct 12, 2025
Before disabling SR-IOV via config space accesses to the parent PF,
sriov_disable() first removes the PCI devices representing the VFs.

Since commit 9d16947 ("PCI: Add global pci_lock_rescan_remove()")
such removal operations are serialized against concurrent remove and
rescan using the pci_rescan_remove_lock. No such locking was ever added
in sriov_disable() however. In particular when commit 18f9e9d
("PCI/IOV: Factor out sriov_add_vfs()") factored out the PCI device
removal into sriov_del_vfs() there was still no locking around the
pci_iov_remove_virtfn() calls.

On s390 the lack of serialization in sriov_disable() may cause double
remove and list corruption with the below (amended) trace being observed:

  PSW:  0704c00180000000 0000000c914e4b38 (klist_put+56)
  GPRS: 000003800313fb48 0000000000000000 0000000100000001 0000000000000001
	00000000f9b520a8 0000000000000000 0000000000002fbd 00000000f4cc9480
	0000000000000001 0000000000000000 0000000000000000 0000000180692828
	00000000818e8000 000003800313fe2c 000003800313fb20 000003800313fad8
  #0 [3800313fb20] device_del at c9158ad5c
  #1 [3800313fb88] pci_remove_bus_device at c915105ba
  #2 [3800313fbd0] pci_iov_remove_virtfn at c9152f198
  #3 [3800313fc28] zpci_iov_remove_virtfn at c90fb67c0
  #4 [3800313fc60] zpci_bus_remove_device at c90fb6104
  #5 [3800313fca0] __zpci_event_availability at c90fb3dca
  #6 [3800313fd08] chsc_process_sei_nt0 at c918fe4a2
  #7 [3800313fd60] crw_collect_info at c91905822
  #8 [3800313fe10] kthread at c90feb390
  #9 [3800313fe68] __ret_from_fork at c90f6aa64
  torvalds#10 [3800313fe98] ret_from_fork at c9194f3f2.

This is because in addition to sriov_disable() removing the VFs, the
platform also generates hot-unplug events for the VFs. This being the
reverse operation to the hotplug events generated by sriov_enable() and
handled via pdev->no_vf_scan. And while the event processing takes
pci_rescan_remove_lock and checks whether the struct pci_dev still exists,
the lack of synchronization makes this checking racy.

Other races may also be possible of course though given that this lack of
locking persisted so long observable races seem very rare. Even on s390 the
list corruption was only observed with certain devices since the platform
events are only triggered by config accesses after the removal, so as long
as the removal finished synchronously they would not race. Either way the
locking is missing so fix this by adding it to the sriov_del_vfs() helper.

Just like PCI rescan-remove, locking is also missing in sriov_add_vfs()
including for the error case where pci_stop_and_remove_bus_device() is
called without the PCI rescan-remove lock being held. Even in the non-error
case, adding new PCI devices and buses should be serialized via the PCI
rescan-remove lock. Add the necessary locking.

Fixes: 18f9e9d ("PCI/IOV: Factor out sriov_add_vfs()")
Signed-off-by: Niklas Schnelle <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Benjamin Block <[email protected]>
Reviewed-by: Farhan Ali <[email protected]>
Reviewed-by: Julian Ruess <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]
heftig pushed a commit that referenced this pull request Oct 12, 2025
The ns_bpf_qdisc selftest triggers a kernel panic:

  Oops[#1]:
  CPU 0 Unable to handle kernel paging request at virtual address 0000000000741d58, era == 90000000851b5ac0, ra == 90000000851b5aa4
  CPU: 0 UID: 0 PID: 449 Comm: test_progs Tainted: G           OE       6.16.0+ #3 PREEMPT(full)
  Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
  Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  pc 90000000851b5ac0 ra 90000000851b5aa4 tp 90000001076b8000 sp 90000001076bb600
  a0 0000000000741ce8 a1 0000000000000001 a2 90000001076bb5c0 a3 0000000000000008
  a4 90000001004c4620 a5 9000000100741ce8 a6 0000000000000000 a7 0100000000000000
  t0 0000000000000010 t1 0000000000000000 t2 9000000104d24d30 t3 0000000000000001
  t4 4f2317da8a7e08c4 t5 fffffefffc002f00 t6 90000001004c4620 t7 ffffffffc61c5b3d
  t8 0000000000000000 u0 0000000000000001 s9 0000000000000050 s0 90000001075bc800
  s1 0000000000000040 s2 900000010597c400 s3 0000000000000008 s4 90000001075bc880
  s5 90000001075bc8f0 s6 0000000000000000 s7 0000000000741ce8 s8 0000000000000000
     ra: 90000000851b5aa4 __qdisc_run+0xac/0x8d8
    ERA: 90000000851b5ac0 __qdisc_run+0xc8/0x8d8
   CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
   PRMD: 00000004 (PPLV0 +PIE -PWE)
   EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
   ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
  ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
   BADV: 0000000000741d58
   PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)]
  Process test_progs (pid: 449, threadinfo=000000009af02b3a, task=00000000e9ba4956)
  Stack : 0000000000000000 90000001075bc8ac 90000000869524a8 9000000100741ce8
          90000001075bc800 9000000100415300 90000001075bc8ac 0000000000000000
          900000010597c400 900000008694a000 0000000000000000 9000000105b59000
          90000001075bc800 9000000100741ce8 0000000000000050 900000008513000c
          9000000086936000 0000000100094d4c fffffff400676208 0000000000000000
          9000000105b59000 900000008694a000 9000000086bf0dc0 9000000105b59000
          9000000086bf0d68 9000000085147010 90000001075be788 0000000000000000
          9000000086bf0f98 0000000000000001 0000000000000010 9000000006015840
          0000000000000000 9000000086be6c40 0000000000000000 0000000000000000
          0000000000000000 4f2317da8a7e08c4 0000000000000101 4f2317da8a7e08c4
          ...
  Call Trace:
  [<90000000851b5ac0>] __qdisc_run+0xc8/0x8d8
  [<9000000085130008>] __dev_queue_xmit+0x578/0x10f0
  [<90000000853701c0>] ip6_finish_output2+0x2f0/0x950
  [<9000000085374bc8>] ip6_finish_output+0x2b8/0x448
  [<9000000085370b24>] ip6_xmit+0x304/0x858
  [<90000000853c4438>] inet6_csk_xmit+0x100/0x170
  [<90000000852b32f0>] __tcp_transmit_skb+0x490/0xdd0
  [<90000000852b47fc>] tcp_connect+0xbcc/0x1168
  [<90000000853b9088>] tcp_v6_connect+0x580/0x8a0
  [<90000000852e7738>] __inet_stream_connect+0x170/0x480
  [<90000000852e7a98>] inet_stream_connect+0x50/0x88
  [<90000000850f2814>] __sys_connect+0xe4/0x110
  [<90000000850f2858>] sys_connect+0x18/0x28
  [<9000000085520c94>] do_syscall+0x94/0x1a0
  [<9000000083df1fb8>] handle_syscall+0xb8/0x158

  Code: 4001ad80  2400873  2400832d <240073cc> 001137ff  001133ff  6407b41f  001503cc  0280041d

  ---[ end trace 0000000000000000 ]---

The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer
is treated as a 32bit value and sign extend to 64bit in epilogue. This
behavior is right for most bpf prog types but wrong for struct ops which
requires LoongArch ABI.

So let's sign extend struct ops return values according to the LoongArch
ABI ([1]) and return value spec in function model.

[1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html

Cc: [email protected]
Fixes: 6abf17d ("LoongArch: BPF: Add struct ops support for trampoline")
Signed-off-by: Hengqi Chen <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>
heftig pushed a commit that referenced this pull request Oct 15, 2025
[ Upstream commit 0b2cd50 ]

generic/091 may fail, then it bisects to the bad commit ba8dac3
("f2fs: fix to zero post-eof page").

What will cause generic/091 to fail is something like below Testcase #1:
1. write 16k as compressed blocks
2. truncate to 12k
3. truncate to 20k
4. verify data in range of [12k, 16k], however data is not zero as
expected

Script of Testcase #1
mkfs.f2fs -f -O extra_attr,compression /dev/vdb
mount -t f2fs -o compress_extension=* /dev/vdb /mnt/f2fs
dd if=/dev/zero of=/mnt/f2fs/file bs=12k count=1
dd if=/dev/random of=/mnt/f2fs/file bs=4k count=1 seek=3 conv=notrunc
sync
truncate -s $((12*1024)) /mnt/f2fs/file
truncate -s $((20*1024)) /mnt/f2fs/file
dd if=/mnt/f2fs/file of=/mnt/f2fs/data bs=4k count=1 skip=3
od /mnt/f2fs/data
umount /mnt/f2fs

Analisys:
in step 2), we will redirty all data pages from #0 to #3 in compressed
cluster, and zero page #3,
in step 3), f2fs_setattr() will call f2fs_zero_post_eof_page() to drop
all page cache post eof, includeing dirtied page #3,
in step 4) when we read data from page #3, it will decompressed cluster
and extra random data to page #3, finally, we hit the non-zeroed data
post eof.

However, the commit ba8dac3 ("f2fs: fix to zero post-eof page") just
let the issue be reproduced easily, w/o the commit, it can reproduce this
bug w/ below Testcase #2:
1. write 16k as compressed blocks
2. truncate to 8k
3. truncate to 12k
4. truncate to 20k
5. verify data in range of [12k, 16k], however data is not zero as
expected

Script of Testcase #2
mkfs.f2fs -f -O extra_attr,compression /dev/vdb
mount -t f2fs -o compress_extension=* /dev/vdb /mnt/f2fs
dd if=/dev/zero of=/mnt/f2fs/file bs=12k count=1
dd if=/dev/random of=/mnt/f2fs/file bs=4k count=1 seek=3 conv=notrunc
sync
truncate -s $((8*1024)) /mnt/f2fs/file
truncate -s $((12*1024)) /mnt/f2fs/file
truncate -s $((20*1024)) /mnt/f2fs/file
echo 3 > /proc/sys/vm/drop_caches
dd if=/mnt/f2fs/file of=/mnt/f2fs/data bs=4k count=1 skip=3
od /mnt/f2fs/data
umount /mnt/f2fs

Anlysis:
in step 2), we will redirty all data pages from #0 to #3 in compressed
cluster, and zero page #2 and #3,
in step 3), we will truncate page #3 in page cache,
in step 4), expand file size,
in step 5), hit random data post eof w/ the same reason in Testcase #1.

Root Cause:
In f2fs_truncate_partial_cluster(), after we truncate partial data block
on compressed cluster, all pages in cluster including the one post eof
will be dirtied, after another tuncation, dirty page post eof will be
dropped, however on-disk compressed cluster is still valid, it may
include non-zero data post eof, result in exposing previous non-zero data
post eof while reading.

Fix:
In f2fs_truncate_partial_cluster(), let change as below to fix:
- call filemap_write_and_wait_range() to flush dirty page
- call truncate_pagecache() to drop pages or zero partial page post eof
- call f2fs_do_truncate_blocks() to truncate non-compress cluster to
  last valid block

Fixes: 3265d3d ("f2fs: support partial truncation on compressed inode")
Reported-by: Jan Prusakowski <[email protected]>
Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Oct 15, 2025
[ Upstream commit f028bca ]

The drm_gem_for_each_gpuvm_bo() call from lookup_vma() accesses
drm_gem_obj.gpuva.list, which is not initialized when the drm driver
does not support DRIVER_GEM_GPUVA feature. Enable it for msm_kms
drm driver to fix the splat seen when msm.separate_gpu_drm=1 modparam
is set:

[    9.506020] Unable to handle kernel paging request at virtual address fffffffffffffff0
[    9.523160] Mem abort info:
[    9.523161]   ESR = 0x0000000096000006
[    9.523163]   EC = 0x25: DABT (current EL), IL = 32 bits
[    9.523165]   SET = 0, FnV = 0
[    9.523166]   EA = 0, S1PTW = 0
[    9.523167]   FSC = 0x06: level 2 translation fault
[    9.523169] Data abort info:
[    9.523170]   ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
[    9.523171]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    9.523172]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    9.523174] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000ad370f000
[    9.523176] [fffffffffffffff0] pgd=0000000000000000, p4d=0000000ad4787403, pud=0000000ad4788403, pmd=0000000000000000
[    9.523184] Internal error: Oops: 0000000096000006 [#1]  SMP
[    9.592968] CPU: 9 UID: 0 PID: 448 Comm: (udev-worker) Not tainted 6.17.0-rc4-assorted-fix-00005-g0e9bb53a2282-dirty #3 PREEMPT
[    9.592970] Hardware name: Qualcomm CRD, BIOS 6.0.240718.BOOT.MXF.2.4-00515-HAMOA-1 07/18/2024
[    9.592971] pstate: a140000 (NzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    9.592973] pc : lookup_vma+0x28/0xe0 [msm]
[    9.592996] lr : get_vma_locked+0x2c/0x128 [msm]
[    9.763632] sp : ffff800082dab460
[    9.763666] Call trace:
[    9.763668]  lookup_vma+0x28/0xe0 [msm] (P)
[    9.763688]  get_vma_locked+0x2c/0x128 [msm]
[    9.763706]  msm_gem_get_and_pin_iova_range+0x68/0x11c [msm]
[    9.763723]  msm_gem_get_and_pin_iova+0x18/0x24 [msm]
[    9.763740]  msm_fbdev_driver_fbdev_probe+0xd0/0x258 [msm]
[    9.763760]  __drm_fb_helper_initial_config_and_unlock+0x288/0x528 [drm_kms_helper]
[    9.763771]  drm_fb_helper_initial_config+0x44/0x54 [drm_kms_helper]
[    9.763779]  drm_fbdev_client_hotplug+0x84/0xd4 [drm_client_lib]
[    9.763782]  drm_client_register+0x58/0x9c [drm]
[    9.763806]  drm_fbdev_client_setup+0xe8/0xcf0 [drm_client_lib]
[    9.763809]  drm_client_setup+0xb4/0xd8 [drm_client_lib]
[    9.763811]  msm_drm_kms_post_init+0x2c/0x3c [msm]
[    9.763830]  msm_drm_init+0x1a8/0x22c [msm]
[    9.763848]  msm_drm_bind+0x30/0x3c [msm]
[    9.919273]  try_to_bring_up_aggregate_device+0x168/0x1d4
[    9.919283]  __component_add+0xa4/0x170
[    9.919286]  component_add+0x14/0x20
[    9.919288]  msm_dp_display_probe_tail+0x4c/0xac [msm]
[    9.919315]  msm_dp_auxbus_done_probe+0x14/0x20 [msm]
[    9.919335]  dp_aux_ep_probe+0x4c/0xf0 [drm_dp_aux_bus]
[    9.919341]  really_probe+0xbc/0x298
[    9.919345]  __driver_probe_device+0x78/0x12c
[    9.919348]  driver_probe_device+0x40/0x160
[    9.919350]  __driver_attach+0x94/0x19c
[    9.919353]  bus_for_each_dev+0x74/0xd4
[    9.919355]  driver_attach+0x24/0x30
[    9.919358]  bus_add_driver+0xe4/0x208
[    9.919360]  driver_register+0x60/0x128
[    9.919363]  __dp_aux_dp_driver_register+0x24/0x30 [drm_dp_aux_bus]
[    9.919365]  atana33xc20_init+0x20/0x1000 [panel_samsung_atna33xc20]
[    9.919370]  do_one_initcall+0x6c/0x1b0
[    9.919374]  do_init_module+0x58/0x234
[    9.919377]  load_module+0x19cc/0x1bd4
[    9.919380]  init_module_from_file+0x84/0xc4
[    9.919382]  __arm64_sys_finit_module+0x1b8/0x2cc
[    9.919384]  invoke_syscall+0x48/0x110
[    9.919389]  el0_svc_common.constprop.0+0xc8/0xe8
[    9.919393]  do_el0_svc+0x20/0x2c
[    9.919396]  el0_svc+0x34/0xf0
[    9.919401]  el0t_64_sync_handler+0xa0/0xe4
[    9.919403]  el0t_64_sync+0x198/0x19c
[    9.919407] Code: eb0000bf 54000480 d100a003 aa0303e2 (f8418c44)
[    9.919410] ---[ end trace 0000000000000000 ]---

Fixes: 217ed15 ("drm/msm: enable separate binding of GPU and display devices")
Signed-off-by: Akhil P Oommen <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Patchwork: https://patchwork.freedesktop.org/patch/672257/
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Oct 15, 2025
commit 8b51b11 upstream.

The ns_bpf_qdisc selftest triggers a kernel panic:

  Oops[#1]:
  CPU 0 Unable to handle kernel paging request at virtual address 0000000000741d58, era == 90000000851b5ac0, ra == 90000000851b5aa4
  CPU: 0 UID: 0 PID: 449 Comm: test_progs Tainted: G           OE       6.16.0+ #3 PREEMPT(full)
  Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
  Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  pc 90000000851b5ac0 ra 90000000851b5aa4 tp 90000001076b8000 sp 90000001076bb600
  a0 0000000000741ce8 a1 0000000000000001 a2 90000001076bb5c0 a3 0000000000000008
  a4 90000001004c4620 a5 9000000100741ce8 a6 0000000000000000 a7 0100000000000000
  t0 0000000000000010 t1 0000000000000000 t2 9000000104d24d30 t3 0000000000000001
  t4 4f2317da8a7e08c4 t5 fffffefffc002f00 t6 90000001004c4620 t7 ffffffffc61c5b3d
  t8 0000000000000000 u0 0000000000000001 s9 0000000000000050 s0 90000001075bc800
  s1 0000000000000040 s2 900000010597c400 s3 0000000000000008 s4 90000001075bc880
  s5 90000001075bc8f0 s6 0000000000000000 s7 0000000000741ce8 s8 0000000000000000
     ra: 90000000851b5aa4 __qdisc_run+0xac/0x8d8
    ERA: 90000000851b5ac0 __qdisc_run+0xc8/0x8d8
   CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
   PRMD: 00000004 (PPLV0 +PIE -PWE)
   EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
   ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
  ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
   BADV: 0000000000741d58
   PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)]
  Process test_progs (pid: 449, threadinfo=000000009af02b3a, task=00000000e9ba4956)
  Stack : 0000000000000000 90000001075bc8ac 90000000869524a8 9000000100741ce8
          90000001075bc800 9000000100415300 90000001075bc8ac 0000000000000000
          900000010597c400 900000008694a000 0000000000000000 9000000105b59000
          90000001075bc800 9000000100741ce8 0000000000000050 900000008513000c
          9000000086936000 0000000100094d4c fffffff400676208 0000000000000000
          9000000105b59000 900000008694a000 9000000086bf0dc0 9000000105b59000
          9000000086bf0d68 9000000085147010 90000001075be788 0000000000000000
          9000000086bf0f98 0000000000000001 0000000000000010 9000000006015840
          0000000000000000 9000000086be6c40 0000000000000000 0000000000000000
          0000000000000000 4f2317da8a7e08c4 0000000000000101 4f2317da8a7e08c4
          ...
  Call Trace:
  [<90000000851b5ac0>] __qdisc_run+0xc8/0x8d8
  [<9000000085130008>] __dev_queue_xmit+0x578/0x10f0
  [<90000000853701c0>] ip6_finish_output2+0x2f0/0x950
  [<9000000085374bc8>] ip6_finish_output+0x2b8/0x448
  [<9000000085370b24>] ip6_xmit+0x304/0x858
  [<90000000853c4438>] inet6_csk_xmit+0x100/0x170
  [<90000000852b32f0>] __tcp_transmit_skb+0x490/0xdd0
  [<90000000852b47fc>] tcp_connect+0xbcc/0x1168
  [<90000000853b9088>] tcp_v6_connect+0x580/0x8a0
  [<90000000852e7738>] __inet_stream_connect+0x170/0x480
  [<90000000852e7a98>] inet_stream_connect+0x50/0x88
  [<90000000850f2814>] __sys_connect+0xe4/0x110
  [<90000000850f2858>] sys_connect+0x18/0x28
  [<9000000085520c94>] do_syscall+0x94/0x1a0
  [<9000000083df1fb8>] handle_syscall+0xb8/0x158

  Code: 4001ad80  2400873  2400832d <240073cc> 001137ff  001133ff  6407b41f  001503cc  0280041d

  ---[ end trace 0000000000000000 ]---

The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer
is treated as a 32bit value and sign extend to 64bit in epilogue. This
behavior is right for most bpf prog types but wrong for struct ops which
requires LoongArch ABI.

So let's sign extend struct ops return values according to the LoongArch
ABI ([1]) and return value spec in function model.

[1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html

Cc: [email protected]
Fixes: 6abf17d ("LoongArch: BPF: Add struct ops support for trampoline")
Signed-off-by: Hengqi Chen <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
heftig pushed a commit that referenced this pull request Oct 17, 2025
Since blamed commit, unregister_netdevice_many_notify() takes the netdev
mutex if the device needs it.

If the device list is too long, this will lock more device mutexes than
lockdep can handle:

unshare -n \
 bash -c 'for i in $(seq 1 100);do ip link add foo$i type dummy;done'

BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by kworker/u16:1/69:
 #0: ..148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work
 #1: ..d40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work
 #2: ..bd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net
 #3: ..aa8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch
 #4: ..cb0 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: unregister_netdevice_many_notify
[..]

Add a helper to close and then unlock a list of net_devices.
Devices that are not up have to be skipped - netif_close_many always
removes them from the list without any other actions taken, so they'd
remain in locked state.

Close devices whenever we've used up half of the tracking slots or we
processed entire list without hitting the limit.

Fixes: 7e4d784 ("net: hold netdev instance lock during rtnetlink operations")
Signed-off-by: Florian Westphal <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
heftig pushed a commit that referenced this pull request Oct 19, 2025
[ Upstream commit 48918ca ]

The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    torvalds#10 0x565358f682bd in cmd_test builtin-test.c:849
    torvalds#11 0x565358ee5ded in run_builtin perf.c:349
    torvalds#12 0x565358ee6085 in handle_internal_command perf.c:401
    torvalds#13 0x565358ee61de in run_argv perf.c:448
    torvalds#14 0x565358ee6527 in main perf.c:555
    torvalds#15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    torvalds#16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    torvalds#17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Oct 19, 2025
commit 0570327 upstream.

Before disabling SR-IOV via config space accesses to the parent PF,
sriov_disable() first removes the PCI devices representing the VFs.

Since commit 9d16947 ("PCI: Add global pci_lock_rescan_remove()")
such removal operations are serialized against concurrent remove and
rescan using the pci_rescan_remove_lock. No such locking was ever added
in sriov_disable() however. In particular when commit 18f9e9d
("PCI/IOV: Factor out sriov_add_vfs()") factored out the PCI device
removal into sriov_del_vfs() there was still no locking around the
pci_iov_remove_virtfn() calls.

On s390 the lack of serialization in sriov_disable() may cause double
remove and list corruption with the below (amended) trace being observed:

  PSW:  0704c00180000000 0000000c914e4b38 (klist_put+56)
  GPRS: 000003800313fb48 0000000000000000 0000000100000001 0000000000000001
	00000000f9b520a8 0000000000000000 0000000000002fbd 00000000f4cc9480
	0000000000000001 0000000000000000 0000000000000000 0000000180692828
	00000000818e8000 000003800313fe2c 000003800313fb20 000003800313fad8
  #0 [3800313fb20] device_del at c9158ad5c
  #1 [3800313fb88] pci_remove_bus_device at c915105ba
  #2 [3800313fbd0] pci_iov_remove_virtfn at c9152f198
  #3 [3800313fc28] zpci_iov_remove_virtfn at c90fb67c0
  #4 [3800313fc60] zpci_bus_remove_device at c90fb6104
  #5 [3800313fca0] __zpci_event_availability at c90fb3dca
  #6 [3800313fd08] chsc_process_sei_nt0 at c918fe4a2
  #7 [3800313fd60] crw_collect_info at c91905822
  #8 [3800313fe10] kthread at c90feb390
  #9 [3800313fe68] __ret_from_fork at c90f6aa64
  torvalds#10 [3800313fe98] ret_from_fork at c9194f3f2.

This is because in addition to sriov_disable() removing the VFs, the
platform also generates hot-unplug events for the VFs. This being the
reverse operation to the hotplug events generated by sriov_enable() and
handled via pdev->no_vf_scan. And while the event processing takes
pci_rescan_remove_lock and checks whether the struct pci_dev still exists,
the lack of synchronization makes this checking racy.

Other races may also be possible of course though given that this lack of
locking persisted so long observable races seem very rare. Even on s390 the
list corruption was only observed with certain devices since the platform
events are only triggered by config accesses after the removal, so as long
as the removal finished synchronously they would not race. Either way the
locking is missing so fix this by adding it to the sriov_del_vfs() helper.

Just like PCI rescan-remove, locking is also missing in sriov_add_vfs()
including for the error case where pci_stop_and_remove_bus_device() is
called without the PCI rescan-remove lock being held. Even in the non-error
case, adding new PCI devices and buses should be serialized via the PCI
rescan-remove lock. Add the necessary locking.

Fixes: 18f9e9d ("PCI/IOV: Factor out sriov_add_vfs()")
Signed-off-by: Niklas Schnelle <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Benjamin Block <[email protected]>
Reviewed-by: Farhan Ali <[email protected]>
Reviewed-by: Julian Ruess <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
heftig pushed a commit that referenced this pull request Oct 19, 2025
Expand the prefault memory selftest to add a regression test for a KVM bug
where KVM's retry logic would result in (breakable) deadlock due to the
memslot deletion waiting on prefaulting to release SRCU, and prefaulting
waiting on the memslot to fully disappear (KVM uses a two-step process to
delete memslots, and KVM x86 retries page faults if a to-be-deleted, a.k.a.
INVALID, memslot is encountered).

To exercise concurrent memslot remove, spawn a second thread to initiate
memslot removal at roughly the same time as prefaulting.  Test memslot
removal for all testcases, i.e. don't limit concurrent removal to only the
success case.  There are essentially three prefault scenarios (so far)
that are of interest:

 1. Success
 2. ENOENT due to no memslot
 3. EAGAIN due to INVALID memslot

For all intents and purposes, #1 and #2 are mutually exclusive, or rather,
easier to test via separate testcases since writing to non-existent memory
is trivial.  But for #3, making it mutually exclusive with #1 _or_ #2 is
actually more complex than testing memslot removal for all scenarios.  The
only requirement to let memslot removal coexist with other scenarios is a
way to guarantee a stable result, e.g. that the "no memslot" test observes
ENOENT, not EAGAIN, for the final checks.

So, rather than make memslot removal mutually exclusive with the ENOENT
scenario, simply restore the memslot and retry prefaulting.  For the "no
memslot" case, KVM_PRE_FAULT_MEMORY should be idempotent, i.e. should
always fail with ENOENT regardless of how many times userspace attempts
prefaulting.

Pass in both the base GPA and the offset (instead of the "full" GPA) so
that the worker can recreate the memslot.

Signed-off-by: Yan Zhao <[email protected]>
Co-developed-by: Sean Christopherson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>
heftig pushed a commit that referenced this pull request Oct 23, 2025
[ Upstream commit 7f0fddd ]

Since blamed commit, unregister_netdevice_many_notify() takes the netdev
mutex if the device needs it.

If the device list is too long, this will lock more device mutexes than
lockdep can handle:

unshare -n \
 bash -c 'for i in $(seq 1 100);do ip link add foo$i type dummy;done'

BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by kworker/u16:1/69:
 #0: ..148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work
 #1: ..d40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work
 #2: ..bd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net
 #3: ..aa8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch
 #4: ..cb0 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: unregister_netdevice_many_notify
[..]

Add a helper to close and then unlock a list of net_devices.
Devices that are not up have to be skipped - netif_close_many always
removes them from the list without any other actions taken, so they'd
remain in locked state.

Close devices whenever we've used up half of the tracking slots or we
processed entire list without hitting the limit.

Fixes: 7e4d784 ("net: hold netdev instance lock during rtnetlink operations")
Signed-off-by: Florian Westphal <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
heftig pushed a commit that referenced this pull request Oct 29, 2025
The original code causes a circular locking dependency found by lockdep.

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S   U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660

but task is already holding lock:

ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
       mutex_lock_nested+0x4e/0xc0
       devcd_data_write+0x27/0x90
       sysfs_kf_bin_write+0x80/0xf0
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
       kernfs_drain+0x1e2/0x200
       __kernfs_remove+0xae/0x400
       kernfs_remove_by_name_ns+0x5d/0xc0
       remove_files+0x54/0x70
       sysfs_remove_group+0x3d/0xa0
       sysfs_remove_groups+0x2e/0x60
       device_remove_attrs+0xc7/0x100
       device_del+0x15d/0x3b0
       devcd_del+0x19/0x30
       process_one_work+0x22b/0x6f0
       worker_thread+0x1e8/0x3d0
       kthread+0x11c/0x250
       ret_from_fork+0x26c/0x2e0
       ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
       __lock_acquire+0x1661/0x2860
       lock_acquire+0xc4/0x2f0
       __flush_work+0x27a/0x660
       flush_delayed_work+0x5d/0xa0
       dev_coredump_put+0x63/0xa0
       xe_driver_devcoredump_fini+0x12/0x20 [xe]
       devm_action_release+0x12/0x30
       release_nodes+0x3a/0x120
       devres_release_all+0x8a/0xd0
       device_unbind_cleanup+0x12/0x80
       device_release_driver_internal+0x23a/0x280
       device_driver_detach+0x14/0x20
       unbind_store+0xaf/0xc0
       drv_attr_store+0x21/0x50
       sysfs_kf_write+0x4a/0x80
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
 Possible unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(&devcd->mutex);
                               lock(kn->active#236);
                               lock(&devcd->mutex);
  lock((work_completion)(&(&devcd->del_wk)->work));
 *** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
 #0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
 #1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
 #2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
 #3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
 #4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S   U              6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 dump_stack+0x10/0x20
 print_circular_bug+0x285/0x360
 check_noncircular+0x135/0x150
 ? register_lock_class+0x48/0x4a0
 __lock_acquire+0x1661/0x2860
 lock_acquire+0xc4/0x2f0
 ? __flush_work+0x25d/0x660
 ? mark_held_locks+0x46/0x90
 ? __flush_work+0x25d/0x660
 __flush_work+0x27a/0x660
 ? __flush_work+0x25d/0x660
 ? trace_hardirqs_on+0x1e/0xd0
 ? __pfx_wq_barrier_func+0x10/0x10
 flush_delayed_work+0x5d/0xa0
 dev_coredump_put+0x63/0xa0
 xe_driver_devcoredump_fini+0x12/0x20 [xe]
 devm_action_release+0x12/0x30
 release_nodes+0x3a/0x120
 devres_release_all+0x8a/0xd0
 device_unbind_cleanup+0x12/0x80
 device_release_driver_internal+0x23a/0x280
 ? bus_find_device+0xa8/0xe0
 device_driver_detach+0x14/0x20
 unbind_store+0xaf/0xc0
 drv_attr_store+0x21/0x50
 sysfs_kf_write+0x4a/0x80
 kernfs_fop_write_iter+0x169/0x220
 vfs_write+0x293/0x560
 ksys_write+0x72/0xf0
 __x64_sys_write+0x19/0x30
 x64_sys_call+0x2bf/0x2660
 do_syscall_64+0x93/0xb60
 ? __f_unlock_pos+0x15/0x20
 ? __x64_sys_getdents64+0x9b/0x130
 ? __pfx_filldir64+0x10/0x10
 ? do_syscall_64+0x1a2/0xb60
 ? clear_bhb_loop+0x30/0x80
 ? clear_bhb_loop+0x30/0x80
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
 </TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.

Fixes: 01daccf ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: [email protected]
Cc: [email protected] # v6.1+
Signed-off-by: Maarten Lankhorst <[email protected]>
Cc: Matthew Brost <[email protected]>
Acked-by: Mukesh Ojha <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
heftig pushed a commit that referenced this pull request Oct 29, 2025
commit a91c809 upstream.

The original code causes a circular locking dependency found by lockdep.

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S   U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660

but task is already holding lock:

ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
       mutex_lock_nested+0x4e/0xc0
       devcd_data_write+0x27/0x90
       sysfs_kf_bin_write+0x80/0xf0
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
       kernfs_drain+0x1e2/0x200
       __kernfs_remove+0xae/0x400
       kernfs_remove_by_name_ns+0x5d/0xc0
       remove_files+0x54/0x70
       sysfs_remove_group+0x3d/0xa0
       sysfs_remove_groups+0x2e/0x60
       device_remove_attrs+0xc7/0x100
       device_del+0x15d/0x3b0
       devcd_del+0x19/0x30
       process_one_work+0x22b/0x6f0
       worker_thread+0x1e8/0x3d0
       kthread+0x11c/0x250
       ret_from_fork+0x26c/0x2e0
       ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
       __lock_acquire+0x1661/0x2860
       lock_acquire+0xc4/0x2f0
       __flush_work+0x27a/0x660
       flush_delayed_work+0x5d/0xa0
       dev_coredump_put+0x63/0xa0
       xe_driver_devcoredump_fini+0x12/0x20 [xe]
       devm_action_release+0x12/0x30
       release_nodes+0x3a/0x120
       devres_release_all+0x8a/0xd0
       device_unbind_cleanup+0x12/0x80
       device_release_driver_internal+0x23a/0x280
       device_driver_detach+0x14/0x20
       unbind_store+0xaf/0xc0
       drv_attr_store+0x21/0x50
       sysfs_kf_write+0x4a/0x80
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
 Possible unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(&devcd->mutex);
                               lock(kn->active#236);
                               lock(&devcd->mutex);
  lock((work_completion)(&(&devcd->del_wk)->work));
 *** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
 #0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
 #1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
 #2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
 #3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
 #4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S   U              6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 dump_stack+0x10/0x20
 print_circular_bug+0x285/0x360
 check_noncircular+0x135/0x150
 ? register_lock_class+0x48/0x4a0
 __lock_acquire+0x1661/0x2860
 lock_acquire+0xc4/0x2f0
 ? __flush_work+0x25d/0x660
 ? mark_held_locks+0x46/0x90
 ? __flush_work+0x25d/0x660
 __flush_work+0x27a/0x660
 ? __flush_work+0x25d/0x660
 ? trace_hardirqs_on+0x1e/0xd0
 ? __pfx_wq_barrier_func+0x10/0x10
 flush_delayed_work+0x5d/0xa0
 dev_coredump_put+0x63/0xa0
 xe_driver_devcoredump_fini+0x12/0x20 [xe]
 devm_action_release+0x12/0x30
 release_nodes+0x3a/0x120
 devres_release_all+0x8a/0xd0
 device_unbind_cleanup+0x12/0x80
 device_release_driver_internal+0x23a/0x280
 ? bus_find_device+0xa8/0xe0
 device_driver_detach+0x14/0x20
 unbind_store+0xaf/0xc0
 drv_attr_store+0x21/0x50
 sysfs_kf_write+0x4a/0x80
 kernfs_fop_write_iter+0x169/0x220
 vfs_write+0x293/0x560
 ksys_write+0x72/0xf0
 __x64_sys_write+0x19/0x30
 x64_sys_call+0x2bf/0x2660
 do_syscall_64+0x93/0xb60
 ? __f_unlock_pos+0x15/0x20
 ? __x64_sys_getdents64+0x9b/0x130
 ? __pfx_filldir64+0x10/0x10
 ? do_syscall_64+0x1a2/0xb60
 ? clear_bhb_loop+0x30/0x80
 ? clear_bhb_loop+0x30/0x80
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
 </TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.

Fixes: 01daccf ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: [email protected]
Cc: [email protected] # v6.1+
Signed-off-by: Maarten Lankhorst <[email protected]>
Cc: Matthew Brost <[email protected]>
Acked-by: Mukesh Ojha <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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2 participants