From: Peter Zijlstra <peterz@infradead.org>
To: eranian@gmail.com
Cc: Vince Weaver <vincent.weaver@maine.edu>,
LKML <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Paul Mackerras <paulus@samba.org>
Subject: Re: perf: easily crash kernel with rapl event close
Date: Thu, 22 Jan 2015 11:17:20 +0100 [thread overview]
Message-ID: <20150122101720.GA2896@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMsRxfJVxUcTvpaUSvTY19Ha93J1R-=o97hO+bfgkL3zU7Nrpw@mail.gmail.com>
On Wed, Jan 21, 2015 at 09:13:11PM -0800, Stephane Eranian wrote:
> Vince,
>
> On Wed, Jan 21, 2015 at 10:55 AM, Vince Weaver <vincent.weaver@maine.edu> wrote:
> > Hello
> >
> > on my haswell system, running 3.19-rc5, and with
> > echo "0" > /proc/sys/kernel/perf_event_paranoid
> >
> > I can easily crash my system with the attached test program that simply
> > opens a RAPL event and then closes it.
> >
> > This bug was found by the perf_fuzzer.
> >
> > It looks like somehow rapl_pmu gets freed to NULL but the
> > call in rapl_scale()
> > __this_cpu_read(rapl_pmu->hw_unit)
> > still happens.
> >
> I don't see how this can happen.
>
> I get some crashes but not with your program on my laptop.
> But I cannot catch the serial console from my laptop.
> Will try with another machine tomorrow.
I saw it today as well on an ivb-ep. I disabled rapl for now since I'm
chasing other things.
next prev parent reply other threads:[~2015-01-22 10:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-21 18:55 perf: easily crash kernel with rapl event close Vince Weaver
2015-01-22 5:13 ` Stephane Eranian
2015-01-22 10:17 ` Peter Zijlstra [this message]
2015-01-22 12:39 ` Stephane Eranian
2015-01-22 16:21 ` Stephane Eranian
2015-01-22 18:20 ` Vince Weaver
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