From: Tejun Heo <tj@xxxxxxxxxx> [ Upstream commit 637fdbae60d6cb9f6e963c1079d7e0445c86ff7d ] If queue_delayed_work() gets called with NULL @wq, the kernel will oops asynchronuosly on timer expiration which isn't too helpful in tracking down the offender. This actually happened with smc. __queue_delayed_work() already does several input sanity checks synchronously. Add NULL @wq check. Reported-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20170227171439.jshx3qplflyrgcv7@xxxxxxxxxxxxxxxxx Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- kernel/workqueue.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 296dcca77f33..181c2ad0cb54 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1506,6 +1506,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, struct timer_list *timer = &dwork->timer; struct work_struct *work = &dwork->work; + WARN_ON_ONCE(!wq); WARN_ON_ONCE(timer->function != delayed_work_timer_fn || timer->data != (unsigned long)dwork); WARN_ON_ONCE(timer_pending(timer)); -- 2.11.0