[PATCH] drm/virtio: Fix GEM handle creation UAF

[Chia-I Wu]

On Fri, Dec 16, 2022 at 3:33 PM Rob Clark <robdclark at gmail.com> wrote:
>
> From: Rob Clark <robdclark at chromium.org>
>
> Userspace can guess the handle value and try to race GEM object creation
> with handle close, resulting in a use-after-free if we dereference the
> object after dropping the handle's reference.  For that reason, dropping
> the handle's reference must be done *after* we are done dereferencing
> the object.
>
> Signed-off-by: Rob Clark <robdclark at chromium.org>
Reviewed-by: Chia-I Wu <olvaffe at gmail.com>