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Date: Sun, 18 May 2008 12:17:44 +0200
From: Andi Kleen <andi@firstfloor.org>
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To: Vegard Nossum <vegard.nossum@gmail.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [PATCH] kmemcheck: support for x86_64
References: <20080517230458.GA18588@damson.getinternet.no>
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> Most of them look something like this:
> 
> kmemcheck: Caught 8-bit read from freed memory (ffff81000780a904)
> ifffffffifffffffifffffffifffffffifffffffifffffffifffffffifffffff
>     ^
> 
> and my theory so far is that X86_64 uses some currently unhandled
> instruction set extensions like MMX, SSE, etc. (Not 3DNow! because we
> have a dependency for that), for a fairly common operation 

No it shouldn't. Only SSE users are in the (broken) MD RAID code

Most likely you don't decode REX correctly in some cases.

[haven't read the patch sorry]

=Andi