Re: 5.0-rc1 KVM inspired "BUG: Bad page state in process" spew

From: Mike Galbraith
Date: Mon Jan 14 2019 - 12:42:25 EST


On Mon, 2019-01-14 at 07:46 -0800, Sean Christopherson wrote:
> On Sat, Jan 12, 2019 at 07:43:02AM +0100, Mike Galbraith wrote:
> > On Wed, 2019-01-09 at 11:26 -0800, Sean Christopherson wrote:
> > >
> > > I'll try to bisect.
> >
> > Good luck with that. I gave it a go, but that apparently invalidated
> > the warrantee of my vm image :)
>
> This is fixed in v5.0-rc2 by commit ba422731316d ("mm/mmu_notifier:
> mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one").

Good to hear.

> Nested VMs are great for bisecting KVM issues :)

I tried nesting dolls (to speed bisection.. hah!), but couldn't
reliable trigger the problem with my reproducer. Even if it had,
nested VMs are pretty cool, but not the _least bit_ fast :)

-Mike