[Bugme-new] [Bug 8778] New: Ocotea board: kernel reports access of bad area during boot with DEBUG_SLAB=y

[Eugene Surovegin]

On Wed, Jul 18, 2007 at 12:52:53AM -0700, Andrew Morton wrote:
> On Wed, 18 Jul 2007 00:07:50 -0700 (PDT) bugme-daemon at bugzilla.kernel.org wrote:
> 
> > http://bugzilla.kernel.org/show_bug.cgi?id=8778
> > 
> >            Summary: Ocotea board: kernel reports access of bad area during
> >                     boot with DEBUG_SLAB=y

Slab debugging is probably the culprit here. I had similar problem 
couple of years ago, not sure something has changed since then, 
haven't checked.

When slab debugging was enabled it made memory allocations non L1 
cache line aligned. This is very bad for DMA on non-coherent cache 
arches (PPC440 is one of those archs).

I have a hack for EMAC which tries to "workaround" this problem:
	http://kernel.ebshome.net/emac_slab_debug.diff
which might help.

-- 
Eugene