On Fri, May 16, 2014 at 12:25:28AM -0400, Vince Weaver wrote: > anyway I'm not sure if it's worth tracking this more if it's possible to > mostly fix the case by fixing the sample_period bounds.
Right, so lets start with that, if it triggers again, we'll have another look. FWIW I ran with the below patch over night, and while trinity completely shat itself going OOM -- so I'm not sure how long it ran, it didn't trigger the stuck interrupt loop. Will do more runs now that I'm there to hold its hand once more. --- Subject: perf: Limit perf_event_attr::sample_period to 63 bits From: Peter Zijlstra <pet...@infradead.org> Date: Thu May 15 20:23:48 CEST 2014 Vince reported that using a large sample_period (one with bit 63 set) results in wreckage since while the sample_period is fundamentally unsigned (negative periods don't make sense) the way we implement things very much rely on signed logic. So limit sample_period to 63 bits to avoid tripping over this. Reported-by: Vince Weaver <vincent.wea...@maine.edu> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmy...@git.kernel.org --- kernel/events/core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7058,6 +7058,9 @@ SYSCALL_DEFINE5(perf_event_open, if (attr.freq) { if (attr.sample_freq > sysctl_perf_event_sample_rate) return -EINVAL; + } else { + if (attr.sample_period & (1ULL << 63)) + return -EINVAL; } /*
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