Page fault in FreeBSD 5.3 on IBM e325, Dual AMD64 2.2GHz, 4GB RAM, ServeRAID 6M - problem goes away without TCP sack

Ganbold ganbold at micom.mng.net
Tue Nov 23 17:22:25 PST 2004


At 06:43 PM 11/22/2004, you wrote:

> >
> > It seems to me the problem is related to network stack and threading.
> > Am I right? How to solve this problem?
>
>I've seen reports of this problem with and without debug.mpsafenet=1,
>which suggests it is a network stack bug but not specific to locking. I've
>also seen reports that disabling TCP SACK will make the problem go away,
>which would be good to confirm.  I spent the weekend building up some more
>expertise in TCP and reading a lot of TCP code, and hope to look at this
>problem in more detail today.  You may want to try turning off TCP sack
>using net.inet.tcp.sack.enable=0 in sysctl.conf (or loader.conf).

I  turned off TCP sack using net.inet.tcp.sack.enable=0 in sysctl.conf and 
it seems like the problem goes away.
It is working for more than 20 hours without any crash.
Robert, did you find anything in network stack code? I'm just curious.

thanks a lot,

Ganbold


>Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
>robert at fledge.watson.org      Principal Research Scientist, McAfee Research
>
>
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