Re: unexpected kernel reboot (3)

From: Dmitry Vyukov
Date: Fri Mar 13 2020 - 03:43:32 EST


On Thu, Mar 12, 2020 at 9:36 PM Jim Mattson <jmattson@xxxxxxxxxx> wrote:
>
> On Wed, Mar 11, 2020 at 1:35 PM Jim Mattson <jmattson@xxxxxxxxxx> wrote:
> >
> > On Wed, Mar 11, 2020 at 1:18 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> >
> > > This happened 10K+ times.
> > > If GCE VM is rebooted by doing something with KVM subsystem, I assume
> > > it's a GCE bug (?). +Jim
> >
> > The L1 guest may have done something that's unsupported, or it may
> > just be a bug in the L0 hypervisor.
>
> I can't reproduce this in GCE with the collateral provided.

As far as I understand, this may depend on GCE host kernel and/or host
CPU, right? Do we have an ability to unit test on all combinations?
Looking at the rate and reproducers on the dashboard I see interesting
patterns. Perhaps the best time to try to reproduce is these periods
when syzbot comes up with lots of reproducers. But it's not now...