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| author | Lai Jiangshan <jiangshan.ljs@antgroup.com> | 2025-01-23 16:25:35 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-21 14:10:47 +0100 |
| commit | 835b69c868f53f959d4986bbecd561ba6f38e492 (patch) | |
| tree | 170af295b35a13c4239370487fdfd86fa9b75e64 /kernel/workqueue.c | |
| parent | 8401cade1918281177974b32c925afdce750d292 (diff) | |
workqueue: Put the pwq after detaching the rescuer from the pool
[ Upstream commit e76946110137703c16423baf6ee177b751a34b7e ]
The commit 68f83057b913("workqueue: Reap workers via kthread_stop() and
remove detach_completion") adds code to reap the normal workers but
mistakenly does not handle the rescuer and also removes the code waiting
for the rescuer in put_unbound_pool(), which caused a use-after-free bug
reported by Cheung Wall.
To avoid the use-after-free bug, the pool’s reference must be held until
the detachment is complete. Therefore, move the code that puts the pwq
after detaching the rescuer from the pool.
Reported-by: cheung wall <zzqq0103.hey@gmail.com>
Cc: cheung wall <zzqq0103.hey@gmail.com>
Link: https://lore.kernel.org/lkml/CAKHoSAvP3iQW+GwmKzWjEAOoPvzeWeoMO0Gz7Pp3_4kxt-RMoA@mail.gmail.com/
Fixes: 68f83057b913("workqueue: Reap workers via kthread_stop() and remove detach_completion")
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9362484a653c..218f8c138808 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3517,12 +3517,6 @@ repeat: } /* - * Put the reference grabbed by send_mayday(). @pool won't - * go away while we're still attached to it. - */ - put_pwq(pwq); - - /* * Leave this pool. Notify regular workers; otherwise, we end up * with 0 concurrency and stalling the execution. */ @@ -3532,6 +3526,12 @@ repeat: worker_detach_from_pool(rescuer); + /* + * Put the reference grabbed by send_mayday(). @pool might + * go away any time after it. + */ + put_pwq_unlocked(pwq); + raw_spin_lock_irq(&wq_mayday_lock); } |