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

devlink: Release nested relation on devlink free

devlink relation state is normally released from devl_unregister(), which
calls devlink_rel_put(). This misses devlink instances that get a nested
relation before registration and then fail probe before devl_register() is
reached.

That flow can happen for SFs. The child devlink gets linked to its
parent before registration, then a later probe error calls devlink_free()
directly. Since the instance was never registered, devl_unregister() is not
called and devlink->rel is leaked.

Release any pending relation from devlink_free() as well. The registered
path is unchanged because devl_unregister() already clears devlink->rel
before devlink_free() runs.