On Thu, Apr 04, 2019 at 12:37:18PM -0400, Vince Weaver wrote: > On Thu, 4 Apr 2019, Cyrill Gorcunov wrote: > > > On Thu, Apr 04, 2019 at 09:25:47AM -0400, Vince Weaver wrote: > > > > > > It looks like there are at least two bugs here, one that's a full > > > hardlockup with nothing on serial console. The other is the NULL > > > dereference. > > OK, it turns out the hard-lock and the null pointer dereference might be > the same, I have a random seed for the fuzzer from a hard-lock crash that > reproduces and it generated the null pointer crash. (This is with your > patch applied).
I see. My patch simply eliminates wrong event for unimplemented general events, but it definitely won't help with nil deref, so it mostly to eliminate some potential side effects. > I can try to see if I can bisect down to a specific event sequence that > triggers this, but that can be tricky sometimes if things lock up so fast > that the event log doesn't get written out before the crash. Oh, Vince, I suspect such kind of bisection might consume a lot of your time :( Maybe we could update perf fuzzer so that it would send events to some net-storage first then write them to the counters, iow to automatize this all stuff somehow?
