Re: [PATCH v12 16/24] vfio: Move vfio_device_group_unregister() to be the first operation in unregister

Jason Gunthorpe
2023-06-23T14:22:50Z

On Fri, Jun 02, 2023 at 05:16:45AM -0700, Yi Liu wrote:
> This avoids endless vfio_device refcount increasement by userspace,
> which would keep blocking the vfio_unregister_group_dev().
>
> Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Tested-by: Terrence Xu <terrence.xu@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
> drivers/vfio/vfio_main.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

It looks OK, at least I couldn't find a reason why the group list
would need to continue to be valid while we are waiting for the
registration lock to release.

Jason