Re: perf: perf_fuzzer crashes on Pentium 4 systems

[Cyrill Gorcunov]

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.
> 

Seems so. I've spent plenty of time yesterday trying to figure out how
we even reach the case when event = nil but without much luck.

> Just ran with your patch applied and it hit the hard lockup case.
> 
> I'll have to see if things are reproducible and I can try to see if I can 
> get a reproducible value for what even caused the issue.  perf_fuzzer has 
> some infrastructure for determining that but it's hit or miss if you can 
> get anything useful from it.

At least the sequence of events migh give us some ideas, maybe not indeed.
Thanks a huge, Vince!

> I'll keep running things, but I'm a bit busy at work here the next few 
> days so there might be some delay in the results.

Sure, take your time. I think this problem with p4 is not urgent. I'll ping
you if I get some more ideas.