From: Oleg Nesterov <oleg@redhat.com>
To: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Cc: christian.koenig@amd.com,
"Eric W. Biederman" <ebiederm@xmission.com>,
David.Panariti@amd.com, amd-gfx@lists.freedesktop.org,
linux-kernel@vger.kernel.org, Alexander.Deucher@amd.com,
akpm@linux-foundation.org
Subject: Re: [PATCH 2/3] drm/scheduler: Don't call wait_event_killable for signaled process.
Date: Mon, 30 Apr 2018 18:00:06 +0200 [thread overview]
Message-ID: <20180430160006.GB10583@redhat.com> (raw)
In-Reply-To: <bceb1a1b-c453-782d-5a7d-40fa2f22c813@amd.com>
On 04/30, Andrey Grodzovsky wrote:
>
> What about changing PF_SIGNALED to PF_EXITING in
> drm_sched_entity_do_release
>
> - if ((current->flags & PF_SIGNALED) && current->exit_code == SIGKILL)
> + if ((current->flags & PF_EXITING) && current->exit_code == SIGKILL)
let me repeat, please don't use task->exit_code. And in fact this check is racy.
But this doesn't matter. Say, we can trivially add SIGNAL_GROUP_KILLED_BY_SIGKILL,
or do something else, but I fail to understand what are you trying to do. Suppose
that the check above is correct in that it is true iff the task is exiting and
it was killed by SIGKILL. What about the "else" branch which does
r = wait_event_killable(sched->job_scheduled, ...)
?
Once again, fatal_signal_pending() (or even signal_pending()) is not well defined
after the exiting task passes exit_signals().
So wait_event_killable() can fail because fatal_signal_pending() is true; and this
can happen even if it was not killed.
Or it can block and SIGKILL won't be able to wake it up.
> If SIGINT was sent then it's SIGINT,
Yes, but see above. in this case fatal_signal_pending() will be likely true so
wait_event_killable() will fail unless condition is already true.
Oleg.
next prev parent reply other threads:[~2018-04-30 16:00 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-24 15:30 Avoid uninterruptible sleep during process exit Andrey Grodzovsky
2018-04-24 15:30 ` Andrey Grodzovsky
2018-04-24 15:30 ` [PATCH 1/3] signals: Allow generation of SIGKILL to exiting task Andrey Grodzovsky
2018-04-24 15:30 ` Andrey Grodzovsky
2018-04-24 16:10 ` Eric W. Biederman
2018-04-24 16:10 ` Eric W. Biederman
2018-04-24 16:42 ` Eric W. Biederman
2018-04-24 16:42 ` Eric W. Biederman
2018-04-24 16:51 ` Andrey Grodzovsky
2018-04-24 16:51 ` Andrey Grodzovsky
2018-04-24 17:29 ` Eric W. Biederman
2018-04-25 13:13 ` Oleg Nesterov
2018-04-24 15:30 ` [PATCH 2/3] drm/scheduler: Don't call wait_event_killable for signaled process Andrey Grodzovsky
2018-04-24 15:30 ` Andrey Grodzovsky
2018-04-24 15:46 ` Michel Dänzer
2018-04-24 15:51 ` Andrey Grodzovsky
2018-04-24 15:51 ` Andrey Grodzovsky
2018-04-24 15:52 ` Andrey Grodzovsky
2018-04-24 15:52 ` Andrey Grodzovsky
2018-04-24 19:44 ` Daniel Vetter
2018-04-24 19:44 ` Daniel Vetter
2018-04-24 21:00 ` Eric W. Biederman
2018-04-24 21:02 ` Andrey Grodzovsky
2018-04-24 21:02 ` Andrey Grodzovsky
2018-04-24 21:21 ` Eric W. Biederman
2018-04-24 21:37 ` Andrey Grodzovsky
2018-04-24 21:37 ` Andrey Grodzovsky
2018-04-24 22:11 ` Eric W. Biederman
2018-04-25 7:14 ` Daniel Vetter
2018-04-25 13:08 ` Andrey Grodzovsky
2018-04-25 13:08 ` Andrey Grodzovsky
2018-04-25 15:29 ` Eric W. Biederman
2018-04-25 16:13 ` Andrey Grodzovsky
2018-04-25 16:31 ` Eric W. Biederman
2018-04-24 21:40 ` Daniel Vetter
2018-04-24 21:40 ` Daniel Vetter
2018-04-25 13:22 ` Oleg Nesterov
2018-04-25 13:36 ` Daniel Vetter
2018-04-25 14:18 ` Oleg Nesterov
2018-04-25 14:18 ` Oleg Nesterov
2018-04-25 13:43 ` Andrey Grodzovsky
2018-04-25 13:43 ` Andrey Grodzovsky
2018-04-24 16:23 ` Eric W. Biederman
2018-04-24 16:23 ` Eric W. Biederman
2018-04-24 16:43 ` Andrey Grodzovsky
2018-04-24 16:43 ` Andrey Grodzovsky
2018-04-24 17:12 ` Eric W. Biederman
2018-04-25 13:55 ` Oleg Nesterov
2018-04-25 14:21 ` Andrey Grodzovsky
2018-04-25 14:21 ` Andrey Grodzovsky
2018-04-25 17:17 ` Oleg Nesterov
2018-04-25 18:40 ` Andrey Grodzovsky
2018-04-25 18:40 ` Andrey Grodzovsky
2018-04-26 0:01 ` Eric W. Biederman
2018-04-26 12:34 ` Andrey Grodzovsky
2018-04-26 12:34 ` Andrey Grodzovsky
2018-04-26 12:52 ` Andrey Grodzovsky
2018-04-26 12:52 ` Andrey Grodzovsky
2018-04-26 15:57 ` Eric W. Biederman
2018-04-26 20:43 ` Andrey Grodzovsky
2018-04-26 20:43 ` Andrey Grodzovsky
2018-04-30 12:08 ` Christian König
2018-04-30 12:08 ` Christian König
2018-04-30 14:32 ` Andrey Grodzovsky
2018-04-30 14:32 ` Andrey Grodzovsky
2018-04-30 15:25 ` Christian König
2018-04-30 15:25 ` Christian König
2018-04-30 16:00 ` Oleg Nesterov [this message]
2018-04-30 16:10 ` Andrey Grodzovsky
2018-04-30 16:10 ` Andrey Grodzovsky
2018-04-30 18:29 ` Christian König
2018-04-30 18:29 ` Christian König
2018-04-30 19:28 ` Andrey Grodzovsky
2018-04-30 19:28 ` Andrey Grodzovsky
2018-05-02 11:48 ` Christian König
2018-05-02 11:48 ` Christian König
2018-05-17 11:18 ` Andrey Grodzovsky
2018-05-17 14:48 ` Michel Dänzer
2018-05-17 15:33 ` Andrey Grodzovsky
2018-05-17 15:52 ` Michel Dänzer
2018-05-17 19:05 ` Andrey Grodzovsky
2018-05-18 8:46 ` Michel Dänzer
2018-05-18 9:42 ` Christian König
2018-05-18 14:44 ` Michel Dänzer
2018-05-18 14:50 ` Christian König
2018-05-18 15:02 ` Andrey Grodzovsky
2018-05-22 12:58 ` Christian König
2018-05-22 15:49 ` Andrey Grodzovsky
2018-05-22 16:09 ` Michel Dänzer
2018-05-22 16:30 ` Andrey Grodzovsky
2018-05-22 16:33 ` Michel Dänzer
2018-05-22 16:37 ` Andrey Grodzovsky
2018-05-01 14:35 ` Oleg Nesterov
2018-05-23 15:08 ` Andrey Grodzovsky
2018-05-23 15:08 ` Andrey Grodzovsky
2018-04-30 15:29 ` Oleg Nesterov
2018-04-30 16:25 ` Eric W. Biederman
2018-04-30 17:18 ` Andrey Grodzovsky
2018-04-30 17:18 ` Andrey Grodzovsky
2018-04-25 13:05 ` Oleg Nesterov
2018-04-24 15:30 ` [PATCH 3/3] drm/amdgpu: Switch to interrupted wait to recover from ring hang Andrey Grodzovsky
2018-04-24 15:30 ` Andrey Grodzovsky
2018-04-24 15:52 ` Panariti, David
2018-04-24 15:52 ` Panariti, David
2018-04-24 15:58 ` Andrey Grodzovsky
2018-04-24 15:58 ` Andrey Grodzovsky
2018-04-24 16:20 ` Panariti, David
2018-04-24 16:20 ` Panariti, David
2018-04-24 16:30 ` Eric W. Biederman
2018-04-24 16:30 ` Eric W. Biederman
2018-04-25 17:17 ` Andrey Grodzovsky
2018-04-25 17:17 ` Andrey Grodzovsky
2018-04-25 20:55 ` Eric W. Biederman
2018-04-25 20:55 ` Eric W. Biederman
2018-04-26 12:28 ` Andrey Grodzovsky
2018-04-26 12:28 ` Andrey Grodzovsky
2018-04-24 16:14 ` Eric W. Biederman
2018-04-24 16:14 ` Eric W. Biederman
2018-04-24 16:38 ` Andrey Grodzovsky
2018-04-24 16:38 ` Andrey Grodzovsky
2018-04-30 11:34 ` Christian König
2018-04-30 11:34 ` Christian König
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