Re: xenstored crashes with SIGSEGV

[Ian Campbell <Ian.Campbell@citrix.com>]

On Thu, 2014-12-18 at 10:49 +0000, Jan Beulich wrote:
> >>> On 18.12.14 at 11:17, <Ian.Campbell@citrix.com> wrote:
> > On Tue, 2014-12-16 at 16:13 +0000, Frediano Ziglio wrote:
> >> Do we have a bug in Xen that affect SSE instructions (possibly already
> >> fixed after Philipp version) ?
> > 
> > I've had a niggling feeling of Deja Vu over this which I'd been putting
> > down to an old Xen on ARM bug in the area of FPU register switching.
> > 
> > But it seems at some point (possibly even still) there was a similar
> > issue with pvops kernels on x86, see:
> >         http://bugs.xenproject.org/xen/bug/40 
> > 
> > Philipp, what kernel are you guys using?
> > 
> > CCing Jan and the x86 kernel guys (and George since he registered the
> > bug). I'm not seeing anything in the kernel logs which looks like a fix
> > (there's some PVH related cr0 frobbing, but I don't think that's it).
> 
> I just went through the thread again and didn't find where kernel/
> hypervisor logs were posted.

I don't think they were yet -- until recently it seemed like a xenstored
bug. Philipp, can you post them now?

Also the patch linked to by David seems like a good thing to try if you
are indeed running a kernel which is susceptible to this issue.

> You mentioning PVH made me want to take a look - said FPU related bug
> would be exposed only by PV kernels.

It's (almost certainly) not a PVH issue, I was saying that the patch
which touched PVH probably isn't relevant to this particular issue.

Ian.