Re: [x86, kaslr] BUG: kernel boot hang

From: Kees Cook
Date: Tue Jan 14 2014 - 18:32:10 EST


On Tue, Jan 14, 2014 at 3:23 PM, H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> 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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