Minor cleanup of MJG's patch on Current list:
unp_dispose and unp_gc can race to teardown the same mbuf chains, which can
lead to dereferencing freed pointers.
To serialize against unp_gc, unp_dispose needs the socket object. Change the dom_dispose() KPI to take a socket object instead of mbuf chain directly.
Unix domain socket code serializes against unp_gc
with a flag on the unpcb under UNP_LIST_LOCK.