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

From: H. Peter Anvin
Date: Tue Jan 14 2014 - 13:47:57 EST


On 01/14/2014 10:26 AM, Kees Cook wrote:
>>
>> [ 0.000000] Base memory trampoline at [ffff880000099000] 99000 size 24576
>> [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
>> [ 0.000000] [mem 0x00000000-0x000fffff] page 4k
>> [ 0.000000] BRK [0x07886000, 0x07886fff] PGTABLE
>> [ 0.000000] BRK [0x07887000, 0x07887fff] PGTABLE
>> [ 0.000000] BRK [0x07888000, 0x07888fff] PGTABLE
>> PANIC: early exception 0e rip 10:ffffffff86204c6e error 0 cr2 ffffffff81972b28
>> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.12.0-rc4-00008-g6e6a493 #614
>> PANIC: early exception 0e rip 10:ffffffff86204f22 error 0 cr2 ffffffff81972b28
>
> I will try to reproduce this, but it's not clear to me what is causing
> the failure. The generated config doesn't look insane to me, so I'm
> not sure what's happening here. Is QEMU doing something unexpected
> with the ordering of where things go for its boot loader?
>

It used to, but I fixed it up a long time ago and now it is really bog
standard.

More likely it just happens to trigger a corner condition, which is
actually a good thing... much easier to debug in a simulator.

-hpa


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