Reuben Farrelly wrote:

tornado.reub.net login: BUG: unable to handle kernel paging request at
virtual address 00200200

This means ct->nat.info.bysource was already removed from the list,
which can only happen if the conntrack entry is destroyed twice.

I can't find how this could have happened, please enable
CONFIG_NETFILTER_DEBUG, the DPRINTK defines in
ip_conntrack_{standalone,core,netlink}.c and ip_nat_{core,standalone}.c
and logging of invalid packets ("echo 255 >
/proc/sys/net/ipv4/netfilter/ip_conntrack_log_invalid"). I hope this
will give some clues ..