drm/qxl: Do not leak memory if qxl_release_list_add fails

[ Upstream commit 8451cc96 ]

If the function fails reference counter to the object is not decremented
causing leaks.
This is hard to spot as it happens only on very low memory situations.
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

drivers/gpu/drm/qxl/qxl_ioctl.c

@@ -122,8 +122,10 @@ static struct qxl_bo *qxlhw_handle_to_bo(struct qxl_device *qdev,
 	qobj = gem_to_qxl_bo(gobj);
 
 	ret = qxl_release_list_add(release, qobj);
-	if (ret)
+	if (ret) {
+		drm_gem_object_unreference_unlocked(gobj);
 		return NULL;
+	}
 
 	return qobj;
 }