Update semaphore.c

kernel/locking/semaphore.c

@@ -32,6 +32,7 @@
 #include <linux/semaphore.h>
 #include <linux/spinlock.h>
 #include <linux/ftrace.h>
+#include <linux/slab.h>  // Required for kmalloc() and kfree()
 
 static noinline void __down(struct semaphore *sem);
 static noinline int __down_interruptible(struct semaphore *sem);
@@ -205,11 +206,14 @@ static inline int __sched __down_common(struct semaphore *sem, long state,
 								long timeout)
 {
 	struct task_struct *task = current;
-	struct semaphore_waiter waiter;
+	struct semaphore_waiter *waiter;
+	waiter = kmalloc(sizeof(*waiter), GFP_KERNEL);
+	if (!waiter)
+	    return -ENOMEM;  // Handle allocation failure
 
-	list_add_tail(&waiter.list, &sem->wait_list);
-	waiter.task = task;
-	waiter.up = false;
+	list_add_tail(&waiter->list, &sem->wait_list);
+	waiter->task = task;
+	waiter->up = false;
 
 	for (;;) {
 		if (signal_pending_state(state, task))
@@ -220,16 +224,21 @@ static inline int __sched __down_common(struct semaphore *sem, long state,
 		raw_spin_unlock_irq(&sem->lock);
 		timeout = schedule_timeout(timeout);
 		raw_spin_lock_irq(&sem->lock);
-		if (waiter.up)
+		if (waiter->up)
+		{
+			kfree(waiter);
 			return 0;
+		}
 	}
 
  timed_out:
-	list_del(&waiter.list);
+	list_del(&waiter->list);
+	kfree(waiter);
 	return -ETIME;
 
  interrupted:
-	list_del(&waiter.list);
+	list_del(&waiter->list);
+	kfree(waiter);
 	return -EINTR;
 }