From: Oleg Nesterov cancel_rearming_delayed_workqueue(dwork) will hang forever if dwork was not scheduled, because in that case cancel_delayed_work()->del_timer_sync() never returns true. I don't know if there are any callers which may have problems, but this is not so convenient, and the fix is very simple. Q: looks like we don't need "struct workqueue_struct *wq" parameter. If the timer was aborted successfully, get_wq_data() == wq. Is it worth to add the new function? Signed-off-by: Oleg Nesterov Cc: Ingo Molnar Signed-off-by: Andrew Morton --- kernel/workqueue.c | 4 ++++ 1 file changed, 4 insertions(+) diff -puN kernel/workqueue.c~workqueue-make-cancel_rearming_delayed_workqueue-work-on-idle-dwork kernel/workqueue.c --- a/kernel/workqueue.c~workqueue-make-cancel_rearming_delayed_workqueue-work-on-idle-dwork +++ a/kernel/workqueue.c @@ -569,6 +569,10 @@ EXPORT_SYMBOL(flush_work_keventd); void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, struct delayed_work *dwork) { + /* Was it ever queued ? */ + if (!get_wq_data(&dwork->work)) + return; + while (!cancel_delayed_work(dwork)) flush_workqueue(wq); } _