mld_set_version() is called only from mld_v1_input_query() and
mld_v2_input_query() both holding the if_addr_mtx lock, and then calling
into mld_v2_cancel_link_timers() acquires it the second time, which results
in mtx recursion. To avoid that, delay if_addr_mtx acquisition until after
mld_set_version() is called; while here, further reduce locking scope
to protect only the needed pieces: if_multiaddrs, in6m_lookup_locked().
PR: kern/158426
Reported by: Thomas <tps vr-web.de>,
Tom Vijlbrief <tom.vijlbrief xs4all.nl>
Tested by: Tom Vijlbrief
Reviewed by: bz
Approved by: re (kib)
0ad2addc9d