In the Linux kernel, the following vulnerability has been resolved:
staging: most: video: avoid double free on video register failure
comp_register_videodev() allocates a video_device with
video_device_alloc() and releases it if video_register_device() fails.
This can double free the video_device when __video_register_device()
reaches device_register() and that call fails:
video_register_device()
-> __video_register_device()
-> device_register() fails
-> put_device(&vdev->dev)
-> v4l2_device_release()
-> vdev->release(vdev)
-> video_device_release(vdev)
comp_register_videodev()
-> video_device_release(mdev->vdev)
Use video_device_release_empty() while registering the device so that
registration failure paths do not free mdev->vdev through vdev->release().
comp_register_videodev() then releases mdev->vdev exactly once on failure.
Restore video_device_release() after successful registration so the
registered device keeps its normal lifetime handling.
This issue was found by a static analysis tool I am developing.
