Memory corruption in powerpc guests with virtio_balloon (was Re: [PATCH v3] virtio_balloon: fix deadlock on OOM)

[Michael Ellerman]

"Michael S. Tsirkin" <mst at redhat.com> writes:
> On Fri, Dec 01, 2017 at 11:31:08PM +1100, Michael Ellerman wrote:
>> "Michael S. Tsirkin" <mst at redhat.com> writes:
>> 
>> > fill_balloon doing memory allocations under balloon_lock
>> > can cause a deadlock when leak_balloon is called from
>> > virtballoon_oom_notify and tries to take same lock.
...
>> 
>> 
>> Somehow this commit seems to be killing powerpc guests.
...
>
> Thanks for the report!
> A fix was just posted:
> virtio_balloon: fix increment of vb->num_pfns in fill_balloon()
>
> Would appreciate testing.

Yep that fixes it. Thanks.

Tested-by: Michael Ellerman <mpe at ellerman.id.au>

cheers