linux-kernel - Re: Cannot boot any HIGHMEM kernel (kernel panic

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Message-ID: <4823576F.5090607@firstfloor.org>
Date:	Thu, 08 May 2008 21:41:35 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Michael Elsdörfer <michael@...doerfer.info>
CC:	linux-kernel@...r.kernel.org
Subject: Re: Cannot boot any HIGHMEM kernel (kernel panic - not syncing)

Michael Elsdörfer wrote:
>>> Now, Machine Check Exception seems to point towards a hardware error,
>>
>> It not only seems to, it does.
>> The non highmem kernel will simply not use most of your memory, so if
>> the machine check happens accessing memory you will not see it.
> 
> Thanks Andi.
> 
> So the problem would be defective RAM in the machine?
> 
> I'm still wondering though while the previous kernel (a self-compiled
> 2.6.17.11) worked then. Laxer checks?

Memory access patterns change between kernels. Likely if you had filled
your memory with some program you would have seen it too.

I always use ftp://ftp.firstfloor.org/pub/ak/memeat.c for testing for
such problems. It simply allocates all free memory and reads and writes
it in a loop.


-Andi


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