Messages in this thread | | | Date | Fri, 8 Nov 2013 21:48:41 +0100 | From | Frederic Weisbecker <> | Subject | Re: perf/tracepoint: another fuzzer generated lockup |
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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 > >
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