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Date: Sat, 24 Nov 2012 09:32:44 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Yinghai Lu <yinghai@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
        Rob Landley <rob@landley.net>, Matt Fleming <matt.fleming@intel.com>
Subject: Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage
 and ramdisk high
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On 11/24/2012 04:37 AM, Eric W. Biederman wrote:
>
> Certainly /sbin/kexec isn't bothering to calculate the end of the setup
> header and just being far more conservative and using all of the 16bit
> real mode code as it's initializer.
>

That's not conservative... that's just plain wrong.  It means you're 
initializing the fields in struct boot_params with garbage instead of a 
predictable value (zero).

We could work around it with a sentinel hack... except you *also* 
probably modify *some* fields and now we have a horrid mix of 
initialized and uninitialized fields to sort out... and there really 
isn't any sane way for the kernel to sort that out.

We have a huge problem on our hands now because of it.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.