Re: panic: m_copym, length > size of mbuf chain

On Wed, 7 Jul 2004, Daniel Lang wrote:

> Dear Robert,
> 
> Robert Watson wrote on Wed, Jul 07, 2004 at 11:11:02AM -0400:
> > What kernel configuration are you running with, and what system tunables?
> [..]
> 
> Bruce Simpson has asked the same thing. I'll just attach my answer to
> him to this mail. 
> 
> It does not, however, include the system tunables, and I cannot include
> a sysctl -a output right now (the machine just crashed again, this time
> again inside of WITNESS, a separate email will document this).  But IIRC
> I have removed all tunables from /etc/sysctl.conf and /boot/loader.conf
> 
> As I told Bruce, I have never set debug.mpsafenet (in case you are
> especially interested in this tunable). 

Yeah, that's one of the ones I was particularly interested in :-).

Just to try ruling out possibilities -- have you run an extensive set of
hardware diagnostics?  Most server class hardware ships with a decent
diagnostics disk, and I'm sure we can find some for you in the event your
hardware didn't come with some.  While it's quite possibly a software
problem, tracking hardware problems using software symptoms constitutes
undesirable pain and so it wouldn't hurt to give that a spin.  I remember
seing your earlier e-mails about running with WITNESS increasing the
chances of pain -- this could be a bug in WITNESS as you suggest, or it
could be that WITNESS increases the opportunities for a variety of locking
related races by increasing the cost of lock/unlock operations.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Principal Research Scientist, McAfee Research