From: ebiederm@xmission.com (Eric W. Biederman)
To: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: <linux-kernel@vger.kernel.org>, <amd-gfx@lists.freedesktop.org>,
<Alexander.Deucher@amd.com>, <Christian.Koenig@amd.com>,
<David.Panariti@amd.com>, <oleg@redhat.com>,
<akpm@linux-foundation.org>
Subject: Re: [PATCH 1/3] signals: Allow generation of SIGKILL to exiting task.
Date: Tue, 24 Apr 2018 11:42:47 -0500 [thread overview]
Message-ID: <87y3hca73s.fsf@xmission.com> (raw)
In-Reply-To: <1524583836-12130-2-git-send-email-andrey.grodzovsky@amd.com> (Andrey Grodzovsky's message of "Tue, 24 Apr 2018 11:30:34 -0400")
Andrey Grodzovsky <andrey.grodzovsky@amd.com> writes:
> Currently calling wait_event_killable as part of exiting process
> will stall forever since SIGKILL generation is suppresed by PF_EXITING.
>
> In our partilaur case AMDGPU driver wants to flush all GPU jobs in
> flight before shutting down. But if some job hangs the pipe we still want to
> be able to kill it and avoid a process in D state.
I should clarify. This absolutely can not be done.
PF_EXITING is set just before a task starts tearing down it's signal
handling.
So delivering any signal, or otherwise depending on signal handling
after PF_EXITING is set can not be done. That abstraction is gone.
Eric
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
> ---
> kernel/signal.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index c6e4c83..c49c706 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -886,10 +886,10 @@ static inline int wants_signal(int sig, struct task_struct *p)
> {
> if (sigismember(&p->blocked, sig))
> return 0;
> - if (p->flags & PF_EXITING)
> - return 0;
> if (sig == SIGKILL)
> return 1;
> + if (p->flags & PF_EXITING)
> + return 0;
> if (task_is_stopped_or_traced(p))
> return 0;
> return task_curr(p) || !signal_pending(p);
WARNING: multiple messages have this Message-ID (diff)
From: ebiederm@xmission.com (Eric W. Biederman)
To: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
Alexander.Deucher@amd.com, Christian.Koenig@amd.com,
David.Panariti@amd.com, oleg@redhat.com,
akpm@linux-foundation.org
Subject: Re: [PATCH 1/3] signals: Allow generation of SIGKILL to exiting task.
Date: Tue, 24 Apr 2018 11:42:47 -0500 [thread overview]
Message-ID: <87y3hca73s.fsf@xmission.com> (raw)
In-Reply-To: <1524583836-12130-2-git-send-email-andrey.grodzovsky@amd.com> (Andrey Grodzovsky's message of "Tue, 24 Apr 2018 11:30:34 -0400")
Andrey Grodzovsky <andrey.grodzovsky@amd.com> writes:
> Currently calling wait_event_killable as part of exiting process
> will stall forever since SIGKILL generation is suppresed by PF_EXITING.
>
> In our partilaur case AMDGPU driver wants to flush all GPU jobs in
> flight before shutting down. But if some job hangs the pipe we still want to
> be able to kill it and avoid a process in D state.
I should clarify. This absolutely can not be done.
PF_EXITING is set just before a task starts tearing down it's signal
handling.
So delivering any signal, or otherwise depending on signal handling
after PF_EXITING is set can not be done. That abstraction is gone.
Eric
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
> ---
> kernel/signal.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index c6e4c83..c49c706 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -886,10 +886,10 @@ static inline int wants_signal(int sig, struct task_struct *p)
> {
> if (sigismember(&p->blocked, sig))
> return 0;
> - if (p->flags & PF_EXITING)
> - return 0;
> if (sig == SIGKILL)
> return 1;
> + if (p->flags & PF_EXITING)
> + return 0;
> if (task_is_stopped_or_traced(p))
> return 0;
> return task_curr(p) || !signal_pending(p);
next prev parent reply other threads:[~2018-04-24 16:44 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 [this message]
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
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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