Re: Commit 7eaceaccab5f40 causing boot hang.

From: Rob Landley
Date: Wed Apr 06 2011 - 07:55:15 EST


On 03/31/2011 07:33 AM, Jens Axboe wrote:
> On 2011-03-31 14:11, Tejun Heo wrote:
>> Hello,
>>
>> On Thu, Mar 31, 2011 at 12:37:42PM +0200, Jens Axboe wrote:
>>> It seems to hard hang, looks very odd:
>> I think more likely failure mode is something is looping in block path
>> expecting someone else to do something but as it is busy looping and
>> preemption isn't enabled the someone else can't proceed. We had a
>> similar problem in md lately.
>>
>> http://thread.gmane.org/gmane.linux.raid/33020
>
> I think this sound exactly right, and also explains why SMP works. And
> yes CONFIG_PREEMPT_VOLUNTARY=y is set.
>
>> If this is the case, a good way to debug would be triggering sysrq-l
>> multiple times while the machine is hung and see where the CPU is busy
>> looping.
>
> Doesn't respond to sysrq. I'll poke around.

Pulled and retested, still hanging for me right after announcing ext3.
Just FYI.

Rob
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/