net80211 related LOR hard hang at reboot

[Kim Culhan]

Running FreeBSD 10-current  r238721M

After issuing a reboot command, the machine hangs and must be power-cycled.

The details of a net80211 related LOR with KDB backtrace is printed
to the console.

In most cases the last item printed to the console before the hard hang is:

pflog0: promiscuous mode disabled

In an unusual case the last line:

Waiting (max 60 seconds) for system process 'bufdaemon' to stop...
(Hangs here..)

Please see attached console pic.

thanks
-kim