Reproducible 5.0.1 GENERIC panic

[Anders Lindgren <ali%df.lth.se@localhost>]

I just noticed that my trusty old Sun Ultra1 firewall, now running 5.0.1 
GENERIC from the 20090729 nightly build, exhibits a trivially reproducible 
panic.

It works just fine gatewaying packets to and from my home LAN, with 
some trivial ipf/ipnat taking place, but if I:

$ ftp -a ftp.netbsd.org
[connect happens]
ftp> cd /pub/NetBSD/packages/5.0
panic: in4_cksum: mbuf too short for IP header

... and then dumps. Unfortunately, savecore doesn't appear to save the 
core into /var/crash, so I guess my ~256MB swap partition is just under 
the 256MB of RAM the machine has in size.

This appears to happen every time (well, twice out of 2 attempts so far), 
so unless this is already a known bug (I didn't find anything matching in 
gnats), I'll sysctl -w ddb.onpanic=1 tomorrow and send-pr.

Best regards,
ali:)