Re: [Qemu-devel] stable/linux-4.14.y boot: 108 boots: 0 failed, 107 passed with 1 conflict (v4.14.11)

[Thomas Gleixner]

On Wed, 3 Jan 2018, Guillaume Tucker wrote:
> On 03/01/18 09:48, Thomas Gleixner wrote:
> > > Well, it turns out this is not exactly a conflict as there's a
> > > subtle difference between the qemu devices in lab-mhart and in
> > > lab-collabora.  The ones in lab-collabora are configured to use
> > > KVM, and it looks like the ones in lab-mhart aren't.
> > > 
> > > So this job with KVM enabled passes in lab-collabora:
> > > 
> > >    https://lava.collabora.co.uk/scheduler/job/1032358
> > > 
> > > but it fails if I tell LAVA (qemu) to disable KVM:
> > > 
> > >    https://lava.collabora.co.uk/scheduler/job/1032359
> > > 
> > > with the same panic as in lab-mhart.  It seems like it's failing
> > > to return from an interrupt:
> > > 
> > >    http://lava.streamtester.net/scheduler/job/87308
> > > 
> > >    [    2.678828]  ? native_iret+0x7/0x7
> > >    [    2.679208] WARNING: can't dereference iret registers at
> > > 00000000ffc66068
> > > for ip page_fault+0x11/0x60
> > > 
> > > This triggered an automated bisection on kernelci.org, please see
> > > the results below.
> > > 
> > > I may run another bisection with this config enabled earlier in
> > > the history to track down the actual change in the code that
> > > introduced the issue, let me know if it's worth doing.
> > 
> > No, because before that commit not all pieces are in place.
> > 
> > Can you please try the failing kernel with pti=off on the command line?
> 
> It does boot with pti=off (and KVM disabled):
> 
>   https://lava.collabora.co.uk/scheduler/job/1032387

So it's a qemu issue. Added qemu folks on Cc.

> > I'll start a test instance here as well.
 
Thanks,

        tglx