Re: perf: perf_fuzzer quickly locks up on 4.15-rc7

[Peter Zijlstra]

On Tue, Jan 09, 2018 at 08:44:23AM -0500, Vince Weaver wrote:
> On Tue, 9 Jan 2018, Peter Zijlstra wrote:
> 
> > So remind me again, how are you running that fuzzer? I'm running
> > ./fast_repro99.sh as root.
> 
> I'm running ./fast_repro98.sh on a regular haswell machine with paranoid 
> set to "0".
> 
> I'll try your patch and see if it makes a difference.

I suspect not, it shouldn't be PTI specific.

> I can also try on a few other machines.  I started setting up a fuzzing 
> cluster for this kind of thing but the multiport serial card I got for 
> logging the serial consoles crashes fairly quickly under load and I 
> haven't had time to track that down.

So I don't think HSW has PT, which is something I cannot test on my IVB.
OTOH HSW has PEBS real_ip, but that uses _less_ magic.

In any case, I found yet another lockdep splat, trying to figure out wth
to do about that. Will then continue running with fast_repro98.