Date: Thu, 24 Mar 2011 13:01:50 -0500 (CDT)
From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@kernel.org>
cc: Ingo Molnar <mingo@elte.hu>, torvalds@linux-foundation.org,
        akpm@linux-foundation.org, tj@kernel.org, npiggin@kernel.dk,
        rientjes@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [GIT PULL] SLAB changes for v2.6.39-rc1
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On Thu, 24 Mar 2011, Pekka Enberg wrote:

> On Thu, Mar 24, 2011 at 7:43 PM, Christoph Lameter <cl@linux.com> wrote:
> > The bug should only trigger on old AMD64 boxes that do not support
> > cmpxchg16b.
>
> Yup. Ingo is it possible to see /proc/cpuinfo of one of the affected
> boxes? I'll try your config but I'm pretty sure the problem doesn't
> trigger here. Like I said, I think the problem is that alternative
> instructions are not patched early enough for cmpxchg16b emulation to
> work for kmem_cache_init(). I tried my check_bugs() patch but it hangs
> during boot. I'll see if I can cook up a patch that does
> alternative_instructions() before kmem_cache_init() because I think
> those *should* be available during boot too.

I forced the fallback to the _emu function to occur but could not trigger
the bug in kvm.

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