Hi Sakari,
On 2017-04-07 04:40 AM, Sakari Ailus wrote:
Hi Helen,
On Thu, Apr 06, 2017 at 04:32:00PM -0300, Helen Koike wrote:
Fix kernel Oops NULL pointer deference
Call dev_dbg_obj only after checking if gobj->mdev is not NULL
Signed-off-by: Helen Koike <[email protected]>
---
drivers/media/media-entity.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 5640ca2..bc44193 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -199,12 +199,12 @@ void media_gobj_create(struct media_device *mdev,
void media_gobj_destroy(struct media_gobj *gobj)
{
- dev_dbg_obj(__func__, gobj);
-
/* Do nothing if the object is not linked. */
if (gobj->mdev == NULL)
return;
+ dev_dbg_obj(__func__, gobj);
+
gobj->mdev->topology_version++;
/* Remove the object from mdev list */
Where is media_gobj_destroy() called with an object with NULL mdev?
I do not object to the change, but would like to know because I don't think
it's supposed to happen.
This happens when media_device_unregister(mdev) is called before
unregistering the subdevices v4l2_device_unregister_subdev(sd) (which
should be possible).
v4l2_device_unregister_subdev(sd) ends up calling v4l2_device_release()
that calls media_device_unregister_entity() again (previously called by
media_device_unregister(mdev)
Helen
There are issues though, until the patches fixing object referencing are
finished and merged. Unfortunately I haven't been able to work on those
recently, will pick them up again soon...
