From: Valentin Schneider <vschneid@redhat.com>
To: paulmck@kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com
Subject: Re: "Dying CPU not properly vacated" splat
Date: Tue, 02 Aug 2022 10:30:02 +0100 [thread overview]
Message-ID: <xhsmhsfmfc7s5.mognet@vschneid.remote.csb> (raw)
In-Reply-To: <20220705172342.GB1790663@paulmck-ThinkPad-P17-Gen-1>
On 05/07/22 10:23, Paul E. McKenney wrote:
> The second of these occurred near shutdown, but the first was quite some
> time before shutdown. In case that makes a difference.
>
> I have not seen this since.
>
> Any other diagnostics I should add?
>
Sorry, I let this get buried to the bottom of my inbox :(
I've had another look at rcutorture.c but just like for
rcu_torture_reader(), I don't see any obvious culprit (no
kthread_set_per_cpu() usage)).
One thing I think would help is a scheduling trace (say sched_switch,
sched_wakeup and cpuhp*, combined with ftrace_dump_on_oops + panic_on_warn
?) - that should at least tell us if the issue is in the wakeup placement
(if the task gets placed on a dying CPU *after* CPUHP_AP_ACTIVE), or in the
balance_push() mechanism (the task was *already* on the CPU when it started
dying and never moved away).
Neither make sense to me, but it has to be somewhere in there...
> Thanx, Paul
next prev parent reply other threads:[~2022-08-02 9:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 19:38 "Dying CPU not properly vacated" splat Paul E. McKenney
2022-04-25 16:15 ` Valentin Schneider
2022-04-25 17:33 ` Paul E. McKenney
2022-04-25 21:59 ` Valentin Schneider
2022-04-26 0:03 ` Paul E. McKenney
2022-04-26 14:48 ` Valentin Schneider
2022-04-26 16:24 ` Paul E. McKenney
2022-06-22 19:58 ` Paul E. McKenney
2022-07-05 7:45 ` Valentin Schneider
2022-07-05 17:23 ` Paul E. McKenney
2022-08-02 9:30 ` Valentin Schneider [this message]
2023-09-06 13:08 ` Paul E. McKenney
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