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Date: Tue, 14 Jan 2014 15:31:43 -0800
Message-ID: <CAGXu5jJLarLeYef0eEfEuVS4pDJf_3my-5BV1O6RX+LP7=hUag@mail.gmail.com>
Subject: Re: [x86, kaslr] BUG: kernel boot hang
From: Kees Cook <keescook@chromium.org>
To: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>, LKML <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org

On Tue, Jan 14, 2014 at 3:23 PM, H. Peter Anvin <hpa@linux.intel.com> wrote:
> On 01/14/2014 02:33 PM, Kees Cook wrote:
>>
>> Can you tell me how the initrd for quantal-core-x86_64.cgz was built
>> in the qemu instances you're using? It seems like all the failures
>> point to a problem with how kASLR is interacting with the initrd.
>>
>
> If kASLR somehow causes the kernel to collide with the initrd that would
> be problem...

Agreed, but I can't reproduce this yet. The initrd is on the list of
areas that get avoided, so the fundamental design isn't broken, but
clearly something is busted.

How long has tip:x86/kaslr been sitting in linux-next? If this is some
interaction between kaslr and something else, perhaps merge order just
happens to be pointing at kaslr?

Regardless, all my tests so far against next-20140114 and an initramfs
haven't seen corruption (using the given .config). I don't have the
same initrd, though, so I'm hoping getting that will trigger the
glitch.

-Kees

-- 
Kees Cook
Chrome OS Security
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