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

From: Michael Ellerman
Date: Sun Dec 03 2017 - 05:04:50 EST


"Michael S. Tsirkin" <mst@xxxxxxxxxx> writes:
> On Fri, Dec 01, 2017 at 11:31:08PM +1100, Michael Ellerman wrote:
>> "Michael S. Tsirkin" <mst@xxxxxxxxxx> 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@xxxxxxxxxxxxxx>

cheers