Re: -CURRENT crashdumps, mbuf corruption

From: Jeremie Le Hen <jeremie_at_le-hen.org>
Date: Mon, 19 Dec 2005 19:14:34 +0100
Hi, Travis,

On Mon, Dec 05, 2005 at 05:27:25PM -0500, Travis Mikalson wrote:
> Hi,
> 
> This looks like an mbuf corruption problem, can you take a look at these?
> http://tog.net/crashdumps/
> 
> I've got two different ones, one seems to involve all of my network 
> interfaces and another seems just to involve if_ath. I'm not an expert 
> at reading this, but both crashes look like they choked on corrupt mbufs.
> 
> I have WITNESS and INVARIANT running in that kernel, I don't know if 
> they are of any use for figuring this problem out.
> 
> Is there any additional information available that I can retrieve that 
> can help? I'm told that mbuf corruption problems are very hard to track 
> down, I'm wondering if there's anything I can do.
> 
> FYI, this box's job in life at the moment while I've got it as 
> stripped-down as possible is to shuffle packets back and forth between 
> one if_ath (in hostap mode) and one if_vr using if_bridge. ipfw is in 
> there somewhere but net.link.bridge.pfil_bridge is off and so is 
> net.link.ether.ipfw and net.link.bridge.ipfw.

Most of the time a stack trace suffices to a commiter to identify the
problem.  Having a kernel dump is good, but it requires to download
a heavy file and this is certainly why you have't got an answer yet.
You should use kgdb on you memory dump to obtain a stack trace and
post it here in conjunction to the FreeBSD version you are using.

Note that making kernel memory dumps publicly available is a security
problem as the memory may contain sensitive informations.

Regards,
-- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >
Received on Mon Dec 19 2005 - 17:15:04 UTC

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