IGMPv3 hot interface detach panics?

[Bruce Simpson]

Can I have some volunteers please...
Sam reports a panic when detaching a card on the fly with the IGMPv3 code.

Whilst I've taken a few precautions in the netisr against this, most 
likely there is something getting used-after-free in the domifdetach 
ping-pong which I've missed in the rush.
So to track this down, I really need a backtrace with full debugging 
symbols. I would encourage anyone who may face a similar issue to try to 
reproduce it with HEAD and send me a full backtrace.

I may not get around to fixing this right away -- already on other stuff 
-- but will try to as time arises.

Many thanks,
BMS