From: Kirill Tkhai <tkhai@yandex.ru>
To: Oleg Nesterov <oleg@redhat.com>,
Kautuk Consul <consul.kautuk@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
Ionut Alexa <ionut.m.alexa@gmail.com>,
Guillaume Morin <guillaume@morinfr.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] do_exit(): Solve possibility of BUG() due to race with try_to_wake_up()
Date: Wed, 03 Sep 2014 13:04:36 +0400 [thread overview]
Message-ID: <3702911409735076@web26g.yandex.ru> (raw)
In-Reply-To: <20140825155738.GA5944@redhat.com>
25.08.2014, 20:01, "Oleg Nesterov" <oleg@redhat.com>:
> 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.
So, if dl_task_timer() is slow (it is unhappy with rq->lock acquiring),
the timer is executing when tasks is already dead.
Kirill
next prev parent reply other threads:[~2014-09-03 9:11 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-25 10:54 [PATCH 1/1] do_exit(): Solve possibility of BUG() due to race with try_to_wake_up() Kautuk Consul
2014-08-25 15:57 ` Oleg Nesterov
2014-08-26 4:45 ` Kautuk Consul
2014-08-26 15:03 ` Oleg Nesterov
2014-09-01 15:39 ` Peter Zijlstra
2014-09-01 17:58 ` Oleg Nesterov
2014-09-01 19:09 ` Peter Zijlstra
2014-09-02 15:52 ` Oleg Nesterov
2014-09-02 16:47 ` Oleg Nesterov
2014-09-02 17:39 ` Peter Zijlstra
2014-09-03 13:36 ` Oleg Nesterov
2014-09-03 14:44 ` Peter Zijlstra
2014-09-03 15:18 ` Oleg Nesterov
2014-09-04 7:15 ` Peter Zijlstra
2014-09-04 17:03 ` Paul E. McKenney
2014-09-04 5:04 ` Ingo Molnar
2014-09-04 6:32 ` Peter Zijlstra
2014-09-03 16:08 ` task_numa_fault() && TASK_DEAD Oleg Nesterov
2014-09-03 16:33 ` Rik van Riel
2014-09-04 7:11 ` Peter Zijlstra
2014-09-04 10:39 ` Oleg Nesterov
2014-09-04 19:14 ` Hugh Dickins
2014-09-05 11:35 ` Oleg Nesterov
2014-09-03 9:04 ` Kirill Tkhai [this message]
2014-09-03 9:45 ` [PATCH 1/1] do_exit(): Solve possibility of BUG() due to race with try_to_wake_up() Peter Zijlstra
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