From: Sultan Alsawaf <sultan@kerneltoast.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Anton Vorontsov <anton@enomsg.org>,
Ben Segall <bsegall@google.com>, Colin Cross <ccross@android.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
dri-devel@lists.freedesktop.org, Ingo Molnar <mingo@redhat.com>,
John Ogness <john.ogness@linutronix.de>,
Juri Lelli <juri.lelli@redhat.com>,
Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>, Mel Gorman <mgorman@suse.de>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Tony Luck <tony.luck@intel.com>,
mkoutny@suse.com
Subject: Re: printk deadlock due to double lock attempt on current CPU's runqueue
Date: Wed, 10 Nov 2021 11:50:30 -0800 [thread overview]
Message-ID: <YYwihj21abVmf9Ag@sultan-box.localdomain> (raw)
In-Reply-To: <CAKfTPtC_A-_sfQ+rm440oHwd2gUZ222FMwsi-JTkyLPc-x0qrw@mail.gmail.com>
On Wed, Nov 10, 2021 at 10:00:35AM +0100, Vincent Guittot wrote:
> Is it the same SCHED_WARN_ON(rq->tmp_alone_branch !=
> &rq->leaf_cfs_rq_list); that generates the deadlock on v5.15 too ?
>
> one remaining tmp_alone_branch warning has been fixed in v5.15 with
> 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
I should clarify that I didn't actually reproduce the issue on v5.15; I just saw
that the call chain leading to the deadlock still existed in v5.15 after looking
through the code.
Failing the SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list); assert
is extremely rare in my experience, and I don't have a reproducer. It has only
happened once after months of heavy usage (with lots of reboots too, so not with
crazy high uptime).
Sultan
next prev parent reply other threads:[~2021-11-10 19:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 20:06 printk deadlock due to double lock attempt on current CPU's runqueue Sultan Alsawaf
2021-11-09 21:38 ` Peter Zijlstra
2021-11-10 9:00 ` Vincent Guittot
2021-11-10 10:45 ` Michal Koutný
2021-11-10 19:50 ` Sultan Alsawaf [this message]
2021-11-12 7:50 ` Vincent Guittot
2021-11-10 9:37 ` Daniel Vetter
2021-11-10 10:07 ` John Ogness
2021-11-10 10:44 ` Daniel Vetter
2021-11-10 20:03 ` Sultan Alsawaf
2021-11-11 8:28 ` John Ogness
2021-11-11 9:27 ` Petr Mladek
2021-11-10 10:50 ` Petr Mladek
2021-11-10 11:20 ` Peter Zijlstra
2021-11-10 13:21 ` Daniel Vetter
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