lock order reversals - what do they mean?

[Christoph P. Kukulies]

On Sun, Dec 14, 2003 at 12:34:59PM -0500, Robert Watson wrote:
> 
> On Sun, 14 Dec 2003, C. Kukulies wrote:
> 
> > I'm getting 
> > lock order reversal
> >  1st 0xc09524c0 UMA lock (UMA lock) @ /u/src/sys/vm/uma_core.c:1200
> >  2nd 0xc1431100 system map (system map) @ /u/src/sys/vm/vm_map.c:2210
> > Stack backtrace:
> > 
> > This happenend while doing a find . something on my notebook hd. 
> 
> These warnings are generated by Witness, a run-time lock diagnostic system
> found in FreeBSD 5-CURRENT kernels (but removed in releases).  You can
> read more about Witness in the WITNESS(4) man page, which talks about its
> capabilities.  Among other things, Witness performs run-time lock order
> verification using a combination of hard coded lock orders, and run-time

Thanks for the information. 

--
Chris Christoph P. U. Kukulies kuku_at_physik.rwth-aachen.de