Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29

From: Meelis Roos
Date: Wed Dec 04 2019 - 14:47:22 EST


04.12.19 17:06 Peter Zijlstra wrote:
On Wed, Dec 04, 2019 at 01:15:40PM +0100, Jiri Olsa wrote:
On Tue, Dec 03, 2019 at 03:39:49PM +0200, Meelis Roos wrote:
Does something like so fix it?

Unfortunately not (tested on top of todays git):

hi,
which p6 model are you seeing this on?
how do you trigger that?

Triggers on any p6 model. I hacked up perf and used "qemu-system-x86_64
-cpu pentium2".

The below seems to cure things.

Yes, works for me on Pentium M. The UBSAN warning is gone and everything seems to work as before.

Thank you!

--
Meelis Roos <mroos@xxxxxxxx>