Re: [PATCH] kmemcheck: support for x86_64

From: Vegard Nossum
Date: Sun May 18 2008 - 07:31:52 EST


On Sun, May 18, 2008 at 12:17 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
>
>> 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.

Thanks. You are right, but you are wrong.

All those #ifdef X86_64 should of course be CONFIG_X86_64... So none
of the 64-bit code was being compiled in. Good spotting, Vegard! :-(


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/