Re: panic: Duplicate free of item 0xffffff005c4a8600 fromzone0xffffff007fed4780(Mbuf)

From: Robert Watson <rwatson_at_freebsd.org>
Date: Mon, 19 Jul 2004 09:58:23 -0400 (EDT)
On Mon, 19 Jul 2004, Willem Jan Withagen wrote:

> > I'll starts some more tests before I'm of to bed.
> 
> This mornings result:
> ====
> System call getdirentries returning with the following locks held:
> exclusive sleep mutex bdone lock r = 0 (0xffffffff805fd080) locked _at_ /home2/src/
> sys/kern/vfs_bio.c:3767
> panic: witness_warn
> cpuid = 0;
> KDB: stack backtrace:
> kdspin lock sched lock held by 0xffffff007b6cc940 for > 5 seconds
> panic: spin lock held too long
> cpuid = 0;
> KDB: enter: panic
> ====
> 
> But no way to get into the debugger.  Does not look like it is much
> network related??? 

Doesn't look very network related, although it could be that increased
concurrency and lack of waiting on Giant open up a race of some sort.  Can
you confirm "options DDB" and "options KDB" are both in your kernel
config?  You may want to consider commenting out "#define PREEMPTION" in
the copy of params.h for the architecture you're running on and see if
that helps.  Won't help interrupt processing latency, but probably won't
hurt server throughput, and your box is a server box so it might be worth
trying. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Principal Research Scientist, McAfee Research
Received on Mon Jul 19 2004 - 11:58:54 UTC

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