2.6.15-mm4 failure on power5

[Dave C Boutcher]

On Wed, Jan 18, 2006 at 11:19:36AM +1100, Michael Ellerman wrote:
> It booted fine _with_ the patch applied, with DEBUG_MUTEXES=y and n.
> 
> Boutcher, to be clear, you can't boot with kernel-kernel-cpuc-to-mutexes.patch 
> applied and DEBUG_MUTEXES=y ?
> 
> But if you revert kernel-kernel-cpuc-to-mutexes.patch it boots ok?
> 
> This is looking quite similar to another hang we're seeing on Power4 iSeries 
> on mainline git:
> http://ozlabs.org/pipermail/linuxppc64-dev/2006-January/007679.html

Correct...I die in exactly the same place every time with
DEBUG_MUTEXES=Y.  I posted a backtrace that points into the _lock_cpu
code, but I haven't really dug into the issue yet.  I believe this is
very timing related (Serge was dying slightly differently).

-- 
Dave Boutcher