On Wed, Sep 03, 2014 at 01:04:36PM +0400, Kirill Tkhai wrote: > 25.08.2014, 20:01, "Oleg Nesterov" <[email protected]>: > > Peter, do you remember another problem with TASK_DEAD we discussed recently? > > (prev_state == TASK_DEAD detection in finish_task_switch() still looks > > racy). > > One more problem with task_dead just to mention it here. > > Below is racy with the change of sched_class: > > if (prev->sched_class->task_dead) > prev->sched_class->task_dead(prev); > > switched_from_dl() does not cancel running timers.
Well, it does a try_to_cancel() but yes, that can fail. Now I suspect you cannot actually do hrtimer_cancel() from switched_from because its called with locks held and the timer function will also try and acquire those locks. But yes, that appears to be an actual problem indeed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
