Messages in this thread | | | Date | Sat, 9 Nov 2013 15:10:39 +0100 | From | Peter Zijlstra <> | Subject | Re: perf/tracepoint: another fuzzer generated lockup |
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On Fri, Nov 08, 2013 at 11:36:58PM +0100, Frederic Weisbecker wrote: > [ 237.627769] perf samples too long (3397569 > 2500), lowering kernel.perf_event_max_sample_rate to 50000 > [ 237.637124] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 444.233 msecs > > 444 msecs is huge.
Be glad your system lived to tell about it ;-) Calling printk() from NMI context is Russian roulette; I'm still waiting for the first report it actually locked up :-)
That said, I'm not sure what kernel you're running, but there were some issues with time-keeping hereabouts, but more importantly that second timing includes the printk() call of the first -- so that's always going to be fucked.
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