From: Zqiang <qiang.zhang@windriver.com> stable inclusion from linux-4.19.156 commit 68e8b8ed787a8acafa3e987d52f6d415c5949ec6 -------------------------------- commit 6993d0fdbee0eb38bfac350aa016f65ad11ed3b1 upstream. There is a small race window when a delayed work is being canceled and the work still might be queued from the timer_fn: CPU0 CPU1 kthread_cancel_delayed_work_sync() __kthread_cancel_work_sync() __kthread_cancel_work() work->canceling++; kthread_delayed_work_timer_fn() kthread_insert_work(); BUG: kthread_insert_work() should not get called when work->canceling is set. Signed-off-by: Zqiang <qiang.zhang@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201014083030.16895-1-qiang.zhang@windriver.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- kernel/kthread.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 7973996e061f..ba1aacf0755a 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -859,7 +859,8 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) /* Move the work from worker->delayed_work_list. */ WARN_ON_ONCE(list_empty(&work->node)); list_del_init(&work->node); - kthread_insert_work(worker, work, &worker->work_list); + if (!work->canceling) + kthread_insert_work(worker, work, &worker->work_list); spin_unlock(&worker->lock); } -- 2.25.1