Request for testers: glibc update to work around Intel TSX errata microcode_ctl problems.

[Hans de Goede]

Hi,

On 09/26/2014 09:26 PM, Siddhesh Poyarekar wrote:
> On Fri, Sep 26, 2014 at 08:53:59PM +0200, Hans de Goede wrote:
>> I've just tested the F-21 update for this, and I'm afraid that the
>> problem is still present there. I've also regenerated my initrd to make
>> sure that that included the new glibc too, but that did not help.
> 
> Do you still see crashes in systemd within pthread code or is it
> something else?  The update should have disabled lock elision
> completely, so if it SIGILLs on haswell, it ought to SIGILL on
> everything, which it doesn't.

I'm still seeing SIGILL in systemd pthread usage. The problem is that the
glibc update still has a code path which uses TSX, see:

https://bugzilla.redhat.com/show_bug.cgi?id=1146967#c14

There is a scratch build here:

http://koji.fedoraproject.org/koji/taskinfo?taskID=7707772

Which fixes the last TSX usage in glibc and I can confirm that that
really fixes things.

> Either way, an early microcode update is indeed the best way out, so
> if that works, we could just drop the glibc update.  But it would be
> great to know what's actually going wrong so that if it's something in
> glibc even with elision disabled, we can get that fixed.

Agreed.

Regards,

Hans