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

[Peter Zijlstra]

On Thu, Jan 11, 2018 at 01:21:12PM -0600, Josh Poimboeuf wrote:
> Yuck.  This time it was stack recursion on the entry stack.  In the
> previous error, recursion was detected on the IRQ stack.  Otherwise they
> look quite similar.
> 
> Was that also with nopti?

Both with pti enabled, nopti makes things work again.

> I haven't had a chance to try it yet, any idea if these would be
> recreatable in a VM?

Good question; typically we run the perf fuzzer on read hardware because
the PMU doesn't virtualize much. But if software perf is enough to
trigger this, that would certainly help.