Re: perf: fuzzer crashes immediately on AMD system

From: Peter Zijlstra
Date: Fri Aug 19 2016 - 06:03:38 EST


On Thu, Aug 18, 2016 at 10:46:31AM -0400, Vince Weaver wrote:
> On Thu, 18 Aug 2016, Vince Weaver wrote:
>
> > Tried the perf_fuzzer on my A10 fam15h/model13h system with 4.8-rc2 and it
> > falls over more or less immediately.
> >
> > This maps to variable_test_bit()
> > called by ctx = find_get_context(pmu, task, event);
> > in kernel/events/core.c:9467
> >
> > It happens quickly enough I can probably track down the exact event that
> > causes this, if needed.
>
> I have a one line reproducer:
>
> perf stat -a -e amd_nb/config=0x37,config1=0x20/ /bin/ls

OK, cannot reproduce on my fam15h/model1h. I'll go dig through the
various manuals to see if I can spot the fail.

Huang could you either prod someone at AMD or do yourself, audit the AMD
perf code for all the various new models?