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Date: Thu, 13 Jul 2006 19:54:19 -0700
From: Andrew Morton <akpm@osdl.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: arjan@infradead.org, torvalds@osdl.org, penberg@cs.helsinki.fi,
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Subject: Re: [patch] lockdep: annotate mm/slab.c
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On Thu, 13 Jul 2006 19:29:52 -0700 (PDT)
Christoph Lameter <clameter@sgi.com> wrote:

> On Thu, 13 Jul 2006, Andrew Morton wrote:
> 
> > > Whew! We drop the list lock before calling slab_destroy.
> > 
> > Well we did, up until about ten minutes ago.
> > 
> > free_block()'s droppage of l3->list_lock around the slab_destroy() call was
> > just reverted, due to Shailabh confirming that it caused corruption.
> 
> How would this slab become corrupted if it is no longer on the lists?

It's a bad sign that this question is flowing in the you->me direction ;)

I don't see anywhere under slab_destroy() where *cachep state gets altered.

The change did cause
free_block->slab_destroy->__cache_free->cache_free_alien to no longer be
called under this slab's l3->list_lock.  Maybe that locking is
(accidentally?) protecting something?