diff options
authorDaniel Vetter <>2019-06-14 08:17:23 +0200
committerDaniel Vetter <>2019-07-10 17:17:14 +0200
commit4f5368b5541a902f6596558b05f5c21a9770dd32 (patch)
parentd006a9b63d4bbb3eb1e2e616712d45acfcda7042 (diff)
drm/kms: Catch mode_object lifetime errors
Only dynamic mode objects, i.e. those which are refcounted and have a free callback, can be added while the overall drm_device is visible to userspace. All others must be added before drm_dev_register and removed after drm_dev_unregister. Small issue around drivers still using the load/unload callbacks, we need to make sure we set dev->registered so that load/unload code in these callbacks doesn't trigger false warnings. Only a small adjustement in drm_dev_register was needed. Motivated by some irc discussions about object ids of dynamic objects like blobs become invalid, and me going on a bit an audit spree. Reviewed-by: Sean Paul <> Signed-off-by: Daniel Vetter <> Link:
2 files changed, 6 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index fe0ce86c280f..c1671ff0f1eb 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -990,14 +990,14 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
if (ret)
goto err_minors;
- dev->registered = true;
if (dev->driver->load) {
ret = dev->driver->load(dev, flags);
if (ret)
goto err_minors;
+ dev->registered = true;
if (drm_core_check_feature(dev, DRIVER_MODESET))
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index 1c6e51135962..c355ba8e6d5d 100644
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -42,6 +42,8 @@ int __drm_mode_object_add(struct drm_device *dev, struct drm_mode_object *obj,
int ret;
+ WARN_ON(dev->registered && !obj_free_cb);
ret = idr_alloc(&dev->mode_config.object_idr, register_obj ? obj : NULL,
1, 0, GFP_KERNEL);
@@ -102,6 +104,8 @@ void drm_mode_object_register(struct drm_device *dev,
void drm_mode_object_unregister(struct drm_device *dev,
struct drm_mode_object *object)
+ WARN_ON(dev->registered && !object->free_cb);
if (object->id) {
idr_remove(&dev->mode_config.object_idr, object->id);