Re: perf_fuzzer crash on pentium 4

Cyrill Gorcunov
2014-05-08T05:38:55Z

On Wed, May 07, 2014 at 10:00:50PM -0400, Don Zickus wrote:
> >
> > If i'm right (btw it's possible to use addr2line helper?) then hwc->config
> > is corrupted and p4_config_get_bind returned nil simply because proper event
> > was not found. And I don't understand how it could happen because before
> > configuration gets written into hwc->config it's validated once obtained
> > from user-space as a raw event. Weird...
>
> I think my commit 13beacee817d27a40ffc6f065ea0042685611dd5 explains this
> corruption. Though I have to admit I haven't looked through the problem
> very closely yet.

nope ;) without the fix above we could (and we did) simply misconfigure
counter but never get access out of array bound. anyway, Vince confirm
the fix from PeterZ healed the problem.

> IOW my lazy fix in that commit doesn't cover fuzzers and the real problem
> in p4_pmu_schedule_events. :-)