From: Frederic Weisbecker <fweisbec@gmail.com>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Jones <davej@redhat.com>
Subject: Re: perf/tracepoint: another fuzzer generated lockup
Date: Fri, 8 Nov 2013 21:48:41 +0100 [thread overview]
Message-ID: <20131108204839.GD14606@localhost.localdomain> (raw)
In-Reply-To: <alpine.DEB.2.10.1311081515210.16519@vincent-weaver-1.um.maine.edu>
On Fri, Nov 08, 2013 at 03:23:07PM -0500, Vince Weaver wrote:
> On Fri, 8 Nov 2013, Frederic Weisbecker wrote:
> >
> > There seem to be a loop that takes too long in intel_pmu_handle_irq(). Your two
> > previous reports seemed to suggest that lbr is involved, but not this one.
>
> I may be wrong but I think everything between <NMI> and <EOE> is just
> noise from the NMI perf-event watchdog timer kicking in.
Ah good point.
So the pattern seem to be that irq work/perf_event_wakeup is involved, may be
interrupting a tracepoint event or so.
It would be nice if you enable CONFIG_FRAME_POINTER in your future reports
so that we get more precise traces. Or may be you actually enabled it and it
doesn't work?
> Why that code would be reading the LBR registers I don't know.
Yeah that's just an inconditional call to check if there is lbr branch to record.
> Vince
>
>
next prev parent reply other threads:[~2013-11-08 20:48 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-08 19:45 perf/tracepoint: another fuzzer generated lockup Vince Weaver
2013-11-08 20:06 ` Vince Weaver
2013-11-08 20:02 ` Frederic Weisbecker
2013-11-08 20:23 ` Vince Weaver
2013-11-08 20:48 ` Frederic Weisbecker [this message]
2013-11-08 21:15 ` Vince Weaver
2013-11-08 22:24 ` Frederic Weisbecker
2013-11-08 22:36 ` Frederic Weisbecker
2013-11-09 1:09 ` Steven Rostedt
2013-11-09 14:10 ` Peter Zijlstra
2013-11-09 14:20 ` Frederic Weisbecker
2013-11-11 12:44 ` Ingo Molnar
2013-11-11 15:53 ` Peter Zijlstra
2013-11-11 21:13 ` Ingo Molnar
2013-11-09 14:52 ` Frederic Weisbecker
2013-11-09 15:13 ` Peter Zijlstra
2013-11-09 15:27 ` Frederic Weisbecker
2013-11-09 15:59 ` Peter Zijlstra
2013-11-09 16:08 ` Frederic Weisbecker
2013-11-09 15:11 ` Peter Zijlstra
2013-11-09 15:22 ` Frederic Weisbecker
2013-11-09 15:30 ` Peter Zijlstra
2013-11-14 15:23 ` Peter Zijlstra
2013-11-14 15:33 ` Peter Zijlstra
2013-11-14 15:35 ` Frederic Weisbecker
2013-11-15 1:16 ` Masami Hiramatsu
2013-11-15 12:28 ` Peter Zijlstra
2013-11-15 14:15 ` Steven Rostedt
2013-11-15 14:28 ` Frederic Weisbecker
2013-11-17 7:53 ` Masami Hiramatsu
2013-11-17 9:43 ` Peter Zijlstra
2013-11-14 16:03 ` Frederic Weisbecker
2013-11-14 17:20 ` Vince Weaver
2013-11-14 17:14 ` Peter Zijlstra
2013-11-14 17:41 ` Steven Rostedt
2013-11-14 19:18 ` Vince Weaver
2013-11-19 19:18 ` [tip:perf/urgent] ftrace, perf: Avoid infinite event generation loop tip-bot for Peter Zijlstra
2013-11-09 0:25 ` perf/tracepoint: another fuzzer generated lockup Frederic Weisbecker
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