[cfarm-users] cfarm427 and cfarm430 crashing

[Jacob Bachmeyer]

On 6/18/25 09:05, Luke Yasuda via cfarm-users wrote:
> Hi!
>
> I've noticed that cfarm427 and cfarm430 (both FreeBSD) have crashed 
> (kernel panic) 2~3 times this month. Anyone has any idea why this happens?

I am less familiar with FreeBSD, but that *looks* like some kind of 
rogue TCP/IPv6 packets are causing crashes in the network code.

It would be very interesting if you could catch the packets that are 
causing this (you might need another box sniffing a mirrored switch port 
with either an unconfigured NIC "raw" or a different (Linux?) kernel) 
and identify what is going wrong.  This *looks* like a remotely 
exploitable DoS in FreeBSD.  I hope it is happening by accident.

A search for 'FreeBSD tcp_do_segment "sent too much"' in search of 
source code led to 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=282605 where it seems 
that there have been similar bugs.  I suggest opening a bug report at 
FreeBSD.  It also looks like FreeBSD has features that can include 
recently-received packets in crash dumps, which solves the need for 
another box to catch the network traffic.


-- Jacob