Date: Wed, 7 Aug 2013 22:53:31 -0400 (EDT)
From: Vince Weaver <vincent.weaver@maine.edu>
To: Vince Weaver <vincent.weaver@maine.edu>
cc: Stephen Boyd <sboyd@codeaurora.org>, Will Deacon <will.deacon@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Mark Rutland <Mark.Rutland@arm.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        "trinity@vger.kernel.org" <trinity@vger.kernel.org>
Subject: Re: perf,arm -- another (different) fuzzer oops
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References: <alpine.DEB.2.10.1308071611290.14098@vincent-weaver-1.um.maine.edu> <20130807223129.GA17118@mudshark.cambridge.arm.com> <5202D5B0.9020107@codeaurora.org> <alpine.DEB.2.10.1308072227060.16962@vincent-weaver-1.um.maine.edu>
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On Wed, 7 Aug 2013, Vince Weaver wrote:

> On Wed, 7 Aug 2013, Stephen Boyd wrote:
> 
> > ---8<----
> > 
> > diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
> > index d9f5cd4..21f7790 100644
> > --- a/arch/arm/kernel/perf_event.c
> > +++ b/arch/arm/kernel/perf_event.c
> > @@ -53,7 +53,12 @@ armpmu_map_cache_event(const unsigned (*cache_map)
> >  static int
> >  armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
> >  {
> > -       int mapping = (*event_map)[config];
> > +       int mapping;
> > +
> > +       if (config >= PERF_COUNT_HW_MAX)
> > +               return -ENOENT;
> > +
> > +       mapping = (*event_map)[config];
> >         return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
> >  }
> 
> I've tested this patch and my testcase no longer causes the kernel to 
> oops, so 
> 
> Tested-by: Vince Weaver <vincent.weaver@maine.edu>

P.S.  I re-ran the fuzzer again after applying the patch and the good news 
      is there were no further oopsen.  The bad news is the machine locked 
      up solid.  I'll investigate further when I'm not remote.

Vince
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