Re: [PATCH v2 vfio 0/3] pds/vfio: Fixes for locking bugs

[Brett Creeley]

On 10/13/2023 2:09 PM, Alex Williamson wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On Wed, 11 Oct 2023 16:01:12 -0700
> Brett Creeley <brett.creeley@xxxxxxx> wrote:
>
> > This series contains fixes for locking bugs in the recently introduced
> > pds-vfio-pci driver. There was an initial bug reported by Dan Carpenter
> > at:
> >
> > https://lore.kernel.org/kvm/1f9bc27b-3de9-4891-9687-ba2820c1b390@moroto.mountain/
> >
> > However, more locking bugs were found when looking into the previously
> > mentioned issue. So, all fixes are included in this series.
> >
> > v2:
> > https://lore.kernel.org/kvm/20230914191540.54946-1-brett.creeley@xxxxxxx/
> > - Trim the OOPs in the patch commit messages
> > - Rework patch 3/3 to only unlock the spinlock once
>
> I thought we determined the spinlock, and thus the atomic context, was
> an arbitrary choice.  I would have figured we simply convert it to a
> mutex.  Why didn't we take that route?  Thanks,
>
> Alex

Hmm. I guess it wasn't completely clear that was the expected solution 
even after Jason's response. However, I can resubmit a v3 with that change.

Thanks,

Brett
> > - Destroy the state_mutex in the driver specific vfio_device_ops.release
> >    callback
> >
> > Brett Creeley (3):
> >    pds/vfio: Fix spinlock bad magic BUG
> >    pds/vfio: Fix mutex lock->magic != lock warning
> >    pds/vfio: Fix possible sleep while in atomic context
> >
> >   drivers/vfio/pci/pds/vfio_dev.c | 27 ++++++++++++++++++++-------
> >   1 file changed, 20 insertions(+), 7 deletions(-)