[ Upstream commit 982b173a6c6d9472730c3116051977e05d17c8c5 ] Userspace can race to free the gobj(robj converted from), robj should not be accessed again after drm_gem_object_put, otherwith it will result in use-after-free. Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Min Li <lm0963hack@gmail.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org>