From: Mark Rutland <mark.rutland@arm.com>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
jeremy.linton@arm.com
Subject: Re: Perf hotplug lockup in v4.9-rc8
Date: Wed, 7 Dec 2016 17:53:47 +0000 [thread overview]
Message-ID: <20161207175347.GB13840@leverpostej> (raw)
In-Reply-To: <20161207135217.GA25605@leverpostej>
On Wed, Dec 07, 2016 at 01:52:17PM +0000, Mark Rutland wrote:
> Hi all
>
> Jeremy noticed a kernel lockup on arm64 when the perf tool was used in
> parallel with hotplug, which I've reproduced on arm64 and x86(-64) with
> v4.9-rc8. In both cases I'm using defconfig; I've tried enabling lockdep
> but it was silent for arm64 and x86.
It looks like we're trying to install a task-bound event into a context
where task_cpu(ctx->task) is dead, and thus the cpu_function_call() in
perf_install_in_context() fails. We retry repeatedly.
On !PREEMPT (as with x86 defconfig), we manage to prevent the hotplug
machinery from making progress, and this turns into a livelock.
On PREEMPT (as with arm64 defconfig), I'm somewhat lost.
Thanks,
Mark.
next prev parent reply other threads:[~2016-12-07 18:03 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 13:53 Perf hotplug lockup in v4.9-rc8 Mark Rutland
2016-12-07 14:30 ` Mark Rutland
2016-12-07 16:39 ` Mark Rutland
2016-12-07 17:53 ` Mark Rutland [this message]
2016-12-07 18:34 ` Peter Zijlstra
2016-12-07 19:56 ` Mark Rutland
2016-12-09 13:59 ` Peter Zijlstra
2016-12-12 11:46 ` Will Deacon
2016-12-12 12:42 ` Peter Zijlstra
2016-12-22 8:45 ` Peter Zijlstra
2016-12-22 14:00 ` Peter Zijlstra
2016-12-22 16:33 ` Paul E. McKenney
2017-01-11 14:59 ` Mark Rutland
2017-01-11 16:03 ` Peter Zijlstra
2017-01-11 16:26 ` Mark Rutland
2017-01-11 19:51 ` Peter Zijlstra
2017-01-14 12:28 ` [tip:perf/urgent] perf/core: Fix sys_perf_event_open() vs. hotplug tip-bot for Peter Zijlstra
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