Re: Bug report: vfio over kernel 5.19 - mm area

[Alex Williamson <alex.williamson@redhat.com>]

On Mon, 15 Aug 2022 18:46:40 +0300
Yishai Hadas <yishaih@nvidia.com> wrote:

> On 15/06/2022 17:02, Alex Williamson wrote:
> > On Wed, 15 Jun 2022 13:52:10 +0300
> > Yishai Hadas <yishaih@nvidia.com> wrote:
> >  
> >> Adding some extra relevant people from the MM area.
> >>
> >> On 15/06/2022 13:43, Yishai Hadas wrote:  
> >>> Hi All,
> >>>
> >>> Any idea what could cause the below break in 5.19 ? we run QEMU and
> >>> immediately the machine is stuck.
> >>>
> >>> Once I run, echo l > /proc/sysrq-trigger could see the below task
> >>> which seems to be stuck..
> >>>
> >>> This basic flow worked fine in 5.18.  
> > Spent Friday bisecting this and posted this fix:
> >
> > https://lore.kernel.org/all/165490039431.944052.12458624139225785964.stgit@omen/
> >
> > I expect you're hotting the same.  Thanks,
> >
> > Alex  
> 
> Alex,
> 
> It seems that we got the same bug again in V6.0 RC1 ..
> 
> The below code [1] from commit [2], put back the 'is_zero_pfn()' under 
> the !(..) and seems buggy.
> 
> I would expect the below fix for that [3].
> 
> Alex Sierra,
> 
> Can you please review the below suggested fix for your patch and send a 
> patch for RC2 accordingly ?
> 

https://lore.kernel.org/all/166015037385.760108.16881097713975517242.stgit@omen/

It's in the mm tree, hopefully it'll get pushed in an early rc.  Thanks,

Alex