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

[Alex Williamson]

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

> - 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(-)
>