This is most likely rhashtable related. The fixes for the
use-after-free issues have been merged Feb 6 so they are probably
not included in the Feb 04 snapshot that you use.
The relevant net-next commits are:
Most likely so - haven't seen this reproducing so far on next-20150219,
which contains the relevant commits.
BTW, why is there no MAINTAINERS entry for the netlink subsystem?