Re: r194546 amd64: kernel panic in tcp_sack.c

Kamigishi Rei wrote:
> Lawrence Stewart wrote:
>> Ok. I'm working on a patch to address a different TCP/SACK issue, but 
>> it may in fact be partially relevant to the cause of your panic... 
>> can't promise when I'll be able to take a close look at this but I'm 
>> aware of it now so that's a start. If you run into it again or find 
>> the trigger for the panic, please let me know.
> Reproduced. I don't know what was the trigger this time. The system runs 
> lighttpd, fastcgi python and php, mysql and postgresql.

hmmm, handy. What is generating the TCP load on this machine? Serving to 
clients on the Internet? Or machines on a local lan? Is there lots of 
load? Little bit?

> Also, in this core somehow everything looks quite similar (looks like 
> another page fault but with panic() called prior to getting into fatal 
> trap 12) to my two earlier dumps:
> http://lists.freebsd.org/pipermail/freebsd-current/2009-June/008777.html
> http://lists.freebsd.org/pipermail/freebsd-current/2009-June/008781.html
> so maybe it's not really a problem with tcp_sack.c or netisr.c.
> 

No, the two earlier panics look like the same issue as one another, but 
they are unrelated to this SACK panic. I've CC'd Robert who might have 
thoughts on the netisr related panics.

> Should I attach the core.txt as well?

Yes, send it to me directly and I'll take a look.

Cheers,
Lawrence