Hi
On 16.01.20 13:57, Hans Verkuil wrote:
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling
v4l2_subdev_release. Therefore it should be set
to NULL so that the subdev won't hold a pointer
to a released object. This fixes a reference
after free bug in function
v4l2_device_unregister_subdev
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op")
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
Reviewed-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
---
changes since v2:
- since this is a regresion fix, I added Fixes and Cc to stable tags,
- change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 63d6b147b21e..2b3595671d62 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd)
{
struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
+ sd->devnode = NULL;
if (sd->internal_ops && sd->internal_ops->release)
sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the
sd->internal_ops->release(sd) callback can still use it.
Unless I am missing something?
It makes sense although none of the drivers uses this callback since
the subdevice should be released in the v4l2_device's release so it
seems that this callback can (should?) be removed.
Dafna
module_put(owner);
Regards,
Hans
