src: add check against non-weak BaseObjects at process exit #35490
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When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: nodejs#35488
Refs: nodejs#35487
Refs: nodejs#35481
addaleax
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addaleax
commented
Oct 3, 2020
| // XXX: The garbage collection rules for ModuleWrap are *super* unclear. | ||
| // Do these objects ever get GC'd? Are we just okay with leaking them? | ||
| return true; | ||
| } |
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I know the bot already pinged the team, but I’d be curious to know if @nodejs/modules knows more about this … especially for ModuleWraps created by the vm module, creating non-GC-able objects can’t be ideal, right…?
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I thought they were all weak at one point?
jasnell
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Oct 4, 2020
Trott
reviewed
Oct 4, 2020
Trott
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Oct 4, 2020
joyeecheung
approved these changes
Oct 4, 2020
benjamingr
approved these changes
Oct 4, 2020
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addaleax
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Oct 7, 2020
When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: #35488
Refs: #35487
Refs: #35481
PR-URL: #35490
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
|
@addaleax This looks caused macOS build failed in github action ../src/env.cc:1227:22: error: lambda capture 'this' is not used [-Werror,-Wunused-lambda-capture]
ForEachBaseObject([this](BaseObject* obj) {
^~~~
1 error generated. |
|
@gengjiawen See #35547 :) |
|
This didn't land cleanly on v14.x, please raise a backport PR if this should land |
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joesepi
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Jan 8, 2021
When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: nodejs#35488
Refs: nodejs#35487
Refs: nodejs#35481
PR-URL: nodejs#35490
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
addaleax
added a commit
to addaleax/node
that referenced
this pull request
May 23, 2021
When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: nodejs#35488
Refs: nodejs#35487
Refs: nodejs#35481
PR-URL: nodejs#35490
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
targos
pushed a commit
that referenced
this pull request
May 25, 2021
When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: #35488
Refs: #35487
Refs: #35481
PR-URL: #35490
Backport-PR-URL: #38786
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
targos
pushed a commit
that referenced
this pull request
Jun 11, 2021
When a process exits cleanly, i.e. because the event loop ends up
without things to wait for, the Node.js objects that are left on
the heap should be:
1. weak, i.e. ready for garbage collection once no longer
referenced, or
2. detached, i.e. scheduled for destruction once no longer
referenced, or
3. an unrefed libuv handle, i.e. does not keep the event loop
alive, or
4. an inactive libuv handle (essentially the same here)
There are a few exceptions to this rule, but generally,
if there are C++-backed Node.js objects on the heap
that do not fall into the above categories, we may be looking
at a potential memory leak. Most likely, the cause is a missing
`MakeWeak()` call on the corresponding object.
In order to avoid this kind of problem, we check the list
of BaseObjects for these criteria. In this commit, we only do so
when explicitly instructed to or when in debug mode
(where --verify-base-objects is always-on).
In particular, this avoids the kinds of memory leak issues
that were fixed in the PRs referenced below.
Refs: #35488
Refs: #35487
Refs: #35481
PR-URL: #35490
Backport-PR-URL: #38786
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
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When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be:
There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing
MakeWeak()call on the corresponding object.In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where
--verify-base-objectsis always-on).In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below (hence the
blockedlabel).Refs: #35488
Refs: #35487
Refs: #35481
Checklist
make -j4 test(UNIX), orvcbuild test(Windows) passes