From: Greg KH <gregkh@linuxfoundation.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Abhijeet Dharmapurikar" <adharmap@quicinc.com>,
"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Daniel Bristot de Oliveira" <bristot@redhat.com>,
"Kees Cook" <keescook@chromium.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Alexey Gladkov" <legion@kernel.org>,
"Kenta.Tada@sony.com" <Kenta.Tada@sony.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Ed Tsai" <ed.tsai@mediatek.com>,
"Valentin Schneider" <valentin.schneider@arm.com>
Subject: Re: [PATCH v3 2/2] sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE
Date: Sun, 10 Apr 2022 08:14:03 +0200 [thread overview]
Message-ID: <YlJ1q0zohdPvQBUd@kroah.com> (raw)
In-Reply-To: <20220409234224.q57dr43bpcll3ryv@airbuntu>
On Sun, Apr 10, 2022 at 12:42:24AM +0100, Qais Yousef wrote:
> +CC stable
>
> On 01/20/22 16:25, Valentin Schneider wrote:
> > TASK_RTLOCK_WAIT currently isn't part of TASK_REPORT, thus a task blocking
> > on an rtlock will appear as having a task state == 0, IOW TASK_RUNNING.
> >
> > The actual state is saved in p->saved_state, but reading it after reading
> > p->__state has a few issues:
> > o that could still be TASK_RUNNING in the case of e.g. rt_spin_lock
> > o ttwu_state_match() might have changed that to TASK_RUNNING
> >
> > As pointed out by Eric, adding TASK_RTLOCK_WAIT to TASK_REPORT implies
> > exposing a new state to userspace tools which way not know what to do with
> > them. The only information that needs to be conveyed here is that a task is
> > waiting on an rt_mutex, which matches TASK_UNINTERRUPTIBLE - there's no
> > need for a new state.
> >
> > Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
>
> Any objection for this to be picked up by stable? We care about Patch 1 only in
> this series for stable, but it seems sensible to pick this one too, no strong
> feeling if it is omitted though.
>
> AFAICT it seems the problem dates back since commit:
>
> 1593baab910d ("sched/debug: Implement consistent task-state printing")
>
> or even before. I think v4.14+ is good enough.
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
next prev parent reply other threads:[~2022-04-10 6:14 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-20 16:25 [PATCH v3 0/2] sched/tracing: sched_switch prev_state reported as TASK_RUNNING when it's not Valentin Schneider
2022-01-20 16:25 ` [PATCH v3 1/2] sched/tracing: Don't re-read p->state when emitting sched_switch event Valentin Schneider
2022-03-01 15:24 ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2022-03-04 16:13 ` Valentin Schneider
2022-03-08 18:02 ` Qais Yousef
2022-03-08 18:10 ` Greg KH
2022-03-08 18:51 ` Qais Yousef
2022-04-09 23:38 ` Qais Yousef
2022-04-10 22:06 ` Qais Yousef
2022-04-10 23:22 ` Holger Hoffstätte
2022-04-11 7:18 ` Holger Hoffstätte
2022-04-11 7:28 ` Greg KH
2022-04-11 8:05 ` Holger Hoffstätte
2022-04-11 13:23 ` Greg KH
2022-04-11 13:22 ` Greg KH
2022-04-11 21:06 ` Qais Yousef
2022-01-20 16:25 ` [PATCH v3 2/2] sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE Valentin Schneider
2022-03-01 15:24 ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2022-04-09 23:42 ` [PATCH v3 2/2] " Qais Yousef
2022-04-10 6:14 ` Greg KH [this message]
2022-04-10 22:13 ` Qais Yousef
2022-04-11 13:20 ` Greg KH
2022-04-11 20:18 ` Qais Yousef
2022-01-21 17:15 ` [PATCH v3 0/2] sched/tracing: sched_switch prev_state reported as TASK_RUNNING when it's not Steven Rostedt
2022-02-27 15:33 ` Peter Zijlstra
2022-04-21 22:12 ` [PATCH] sched/tracing: append prev_state to tp args instead Delyan Kratunov
2022-04-22 10:13 ` Valentin Schneider
2022-04-22 11:09 ` Peter Zijlstra
2022-04-22 15:55 ` Steven Rostedt
2022-04-22 16:54 ` Andrii Nakryiko
2022-04-22 16:37 ` Andrii Nakryiko
2022-04-22 17:22 ` Delyan Kratunov
2022-04-22 18:30 ` Alexei Starovoitov
2022-04-26 12:28 ` Peter Zijlstra
2022-04-26 14:09 ` Qais Yousef
2022-04-26 15:54 ` Andrii Nakryiko
2022-04-27 10:34 ` Qais Yousef
2022-04-27 18:17 ` Andrii Nakryiko
2022-04-27 20:32 ` Alexei Starovoitov
2022-04-28 10:02 ` Qais Yousef
2022-05-09 19:32 ` Andrii Nakryiko
2022-05-10 7:01 ` Peter Zijlstra
2022-05-10 8:29 ` Peter Zijlstra
2022-05-10 14:31 ` Steven Rostedt
2022-05-11 18:28 ` [PATCH v2] " Delyan Kratunov
2022-05-11 19:10 ` Steven Rostedt
2022-05-11 22:45 ` [tip: sched/urgent] sched/tracing: Append " tip-bot2 for Delyan Kratunov
2022-05-11 23:40 ` [PATCH v2] sched/tracing: append " Thomas Gleixner
2022-04-26 15:51 ` [PATCH] " Andrii Nakryiko
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