6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavankumar Kondeti commit 980db94e3eeefdd8a1c46f86412c33a7f7806f51 upstream. current_wq_worker() only tells us that %current is a kworker. It does not guarantee that the worker is currently executing a work item, as worker->current_pwq is populated only while process_one_work() is running the work function. is_chained_work() can be reached while queueing on a draining or destroying workqueue. If a kworker outside work-item execution reaches that path, current_wq_worker() returns a worker but worker->current_pwq is NULL, and the chained-work test can fault before it emits the intended warning. Guard the chained-work test with worker->current_pwq. A kworker without current_pwq is not executing work on the target workqueue, so the helper should return false and let the draining/destroying warning fire. Fixes: 8d03ecfe4718 ("workqueue: reimplement is_chained_work() using current_wq_worker()") Cc: stable@vger.kernel.org Signed-off-by: Pavankumar Kondeti Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2235,7 +2235,7 @@ static bool is_chained_work(struct workq * Return %true iff I'm a worker executing a work item on @wq. If * I'm @worker, it's safe to dereference it without locking. */ - return worker && worker->current_pwq->wq == wq; + return worker && worker->current_pwq && worker->current_pwq->wq == wq; } /*