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From: Pete French <petefrench@ticketswitch.com>
Date: Fri, 16 Jan 2009 15:40:11 +0000
Cc: freebsd-stable@freebsd.org
Subject: Re: Big problems with 7.1 locking up :-(
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> If you do INVARIANTS + WITNESS + WITNESS_SKIPSPIN, that should be good. 
> WITNESS does a number of things, including tracking (and being judgemental 
> about) lock order.  One nice side effect of that tracking is that we keep 
> track of a lot more lock state explicitly, so DDB's "show allocks", "show 
> locks", etc, commands can build on that.  "show lockedvnods" works without 
> WITNESS, though, so your results so far suggest this is likely not related to 
> vnode locking.

Right, I've gone back to my DEBUG kernel which has a lot of options in it,
including all the above. It has locked almost immediately luckily, so
now I have it sitting at the debugger prompt. The output from 'show alllocks'
is here:

http://toybox.twisted.org.uk/~pete/71_show_alllocks.png

Which of these are worth tracing ?

-pte.