Re: unexpected kernel reboot (3)

[Dmitry Vyukov]

On Fri, Mar 13, 2020 at 8:43 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>
> 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...


These unexpected VM reboots continue to happen. I can reproduce them
on GCE, but not in qemu.
Jim, Peter, Ben, I can give you access to a VM I just used to
reproduce the reboot.
Here is the latest repro I used:
https://gist.github.com/dvyukov/e9ddb9c3f1117f8cfd85713cf44d81bd