github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

workqueue: BUG_ON() a pwq release before workqueue_init()

Browse Source 
put_pwq() bounces the release to pwq_release_worker to get out from
under pool->lock. workqueue_init() creates that kthread_worker well
after workqueue_init_early() has built the system workqueues, so a pwq
allocation failing partway through apply_wqattrs_prepare() unwinds
through apply_wqattrs_cleanup() and dereferences a NULL worker.

There is no way back from that. Running the release inline is not an
option, that is what the bounce exists for, and workqueue_init_early()
already BUG_ON()s a system workqueue it failed to allocate.

BUG_ON() the missing worker instead of oopsing inside
kthread_queue_work().

Suggested-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/all/144b3dc986135ebe34f671cdd02bd8aa@kernel.org/
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Breno Leitao 2026-09-11 03:26:28 -07:00 committed by Tejun Heo
parent d8c2ce77cd
commit 9d4815c14f
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
kernel/workqueue.c
View File

@ -1771,6 +1771,14 @@ static void put_pwq(struct pool_workqueue *pwq)
lockdep_assert_held(&pwq->pool->lock);
if (likely(--pwq->refcnt))
return;
/*
* pwq_release_worker is only created in workqueue_init(). Getting
* here before that means an early workqueue allocation failed, which
* is fatal anyway.
*/
BUG_ON(!pwq_release_worker);
/*
* @pwq can't be released under pool->lock, bounce to a dedicated
* kthread_worker to avoid A-A deadlocks.