4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tejun Heo tj@kernel.org
[ 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@codemonkey.org.uk Link: http://lkml.kernel.org/r/20170227171439.jshx3qplflyrgcv7@codemonkey.org.uk Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/workqueue.c | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1506,6 +1506,7 @@ static void __queue_delayed_work(int cpu 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));