Re: Early boot panic on machine with lots of memory

From: Yinghai Lu
Date: Thu Jun 14 2012 - 16:56:25 EST


On Thu, Jun 14, 2012 at 2:50 AM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote:
> On Thu, 2012-06-14 at 12:20 +0900, Tejun Heo wrote:
>> On Wed, Jun 13, 2012 at 11:38:55PM +0200, Sasha Levin wrote:
>> > Hi all,
>> >
>> > I'm seeing the following when booting a KVM guest with 65gb of RAM, on latest linux-next.
>> >
>> > Note that it happens with numa=off.
>> >
>> > [    0.000000] BUG: unable to handle kernel paging request at ffff88102febd948
>> > [    0.000000] IP: [<ffffffff836a6f37>] __next_free_mem_range+0x9b/0x155
>>
>> Can you map it back to the source line please?
>
> mm/memblock.c:583
>
>                        phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0;
>  97:   85 d2                   test   %edx,%edx
>  99:   74 08                   je     a3 <__next_free_mem_range+0xa3>
>  9b:   49 8b 48 f0             mov    -0x10(%r8),%rcx
>  9f:   49 03 48 e8             add    -0x18(%r8),%rcx
>
> It's the deref on 9b (r8=ffff88102febd958).

that reserved.region is allocated by memblock.

can you boot with "memblock=debug debug ignore_loglevel" and post
whole boot log?

Thanks

Yinghai
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