Hi -
if_detach() causes a panic if an interface was put into an IPv6
multicast group.
This is caused by the assumption that the addresses are removed
one-by-one. In the ipv6 case however, multiple interface addresses
can disappear in the course of one PRU_PURGEIF call.
The appended patch fixes the list walking.
It strictly assumes that the is only one AF_LINK address per interface
and that it is the first in the list.
Are there cases where this might not hold?

best regards
Matthias