[ was: Re: [PATCH] [gdb/testsuite] Add have_linux_btrace_bug ]
On 2/13/23 20:17, Metzger, Markus T wrote:
> Hello Tom,
> 
>> The linux kernel commit 670638477aed ("perf/x86/intel/pt: Opportunistically
>> use single range output mode"), added in version v5.5.0 had a bug that was
>> fixed by commit ce0d998be927 ("perf/x86/intel/pt: Fix sampling using
>> single range output") in version 6.1.0.
>>
>> The bug manifested for intel microarchitectures Rocket Lake, Raptor Lake and
>> Alder Lake.
> 
> Actually, it's a h/w bug that got exposed by using single-range output.  It affects
> Core processors starting from Ice Lake and it only affects Processor Trace.  Also,
> it is only exposed by the py-record-btrace test, which does a lot of single-stepping.
> 
> It might be better to just add an XFAIL for that one test.  I'm not sure if maintaining
> a processor list makes sense.  The kernel patch disables single-range for > 1 page
> for all processors and does not try to maintain a list of affected processors.  We might
> want to do the same in GDB and either disable that test for kernels between 5.5 and
> 6.1, or setup an XFAIL.
> 

I've gone with the XFAIL, see attached patch.  WDYT?

> The Branch Trace Store issue you found seems to affect all btrace tests on ADL
> E-cores.  This is a different issue.  I can reproduce it and I am currently debugging it.

I see, ack, thanks for the update.

- Tom