In the Linux kernel, the following vulnerability has been resolved: media: v4l2-async: avoid deleting unlinked ASC entry on link error v4l

In the Linux kernel, the following vulnerability has been resolved:

media: v4l2-async: avoid deleting unlinked ASC entry on link error

v4l2_async_match_notify() creates ancillary media links before adding
asc->asc_subdev_entry to sd->asc_list.

If ancillary link creation fails, the function jumps to
err_call_unbind while asc_subdev_entry has not been linked yet. Async
connections are zero-allocated, so the list entry still has NULL next
and prev pointers on this path. Calling list_del() on it can therefore
dereference NULL instead of returning the original link creation error.

Do not delete asc_subdev_entry from err_call_unbind. There is no list
insertion to undo on this path; the bound callback and sub-device
registration are the operations that need to be rolled back.