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Date: Mon, 13 Jun 2011 12:59:57 -0500 (CDT)
From: Christoph Lameter <cl@linux.com>
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To: Hugh Dickins <hughd@google.com>
cc: Pekka Enberg <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] slub: fix kernel BUG at mm/slub.c:1950!
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On Sun, 12 Jun 2011, Hugh Dickins wrote:

> 3.0-rc won't boot with SLUB on my PowerPC G5: kernel BUG at mm/slub.c:1950!
> Bisected to 1759415e630e "slub: Remove CONFIG_CMPXCHG_LOCAL ifdeffery".
>
> After giving myself a medal for finding the BUG on line 1950 of mm/slub.c
> (it's actually the
> 	VM_BUG_ON((unsigned long)(&pcp1) % (2 * sizeof(pcp1)));
> on line 268 of the morass that is include/linux/percpu.h)
> I tried the following alignment patch and found it to work.

Hmmm.. The allocpercpu in alloc_kmem_cache_cpus should take care of the
alignment. Uhh.. I see that a patch that removes the #ifdef CMPXCHG_LOCAL
was not applied? Pekka?