3.9-rc1: crash kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer

[Yinghai Lu]

On Thu, Mar 7, 2013 at 10:32 PM, Yinghai Lu <yinghai at kernel.org> wrote:
> On Thu, Mar 7, 2013 at 10:03 PM, CAI Qian <caiqian at redhat.com> wrote:
>> CC'ing kexec ML. Also mentioned that 3.8 has no such issue.
>>
>> This message looks suspicious and out of range while 3.8 reservation
>> looks within the range.
>>
>> [    0.000000] Reserving 128MB of memory at 5216MB for crashkernel
>> (System RAM: 3977MB)
>>
>> Wondering if anything to do with memblock again...
>
> that is intended...
>
>> ----- Original Message -----
>>> From: "WANG Chao" <chaowang at redhat.com>
>>> To: "LKML" vger.kernel.org>
>>> Cc: "CAI Qian" <caiqian at redhat.com>
>>> Sent: Friday, March 8, 2013 1:54:37 PM
>>> Subject: 3.9-rc1: crash kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you
>>> with the DMA bounce buffer
>>>
>>> Hi, All
>>>
>>> On 3.9-rc1, I load crash kernel with latest kexec-tools(up to
>>> 28d413a), but
>>> 2nd kernel panic at early time:
>>> [    2.948076] Kernel panic - not syncing: Can not allocate SWIOTLB
>>> buffer earlier and can't now provide you with the DMA bounce buffer
>>> [    2.959958] Pid: 53, comm: khubd Not tainted 3.9.0-rc1+ #1
>
> You need to add crashkernel_low=64M in first kernel.
>
> As your system does not support DMA remapping.

looks like your system DO have DMAR table, please enable dmar
remapping in your kernel config.

Yinghai