Re: [BUG] kernel BUG at /.../block/cfq-iosched.c:3145!

[Jens Axboe <axboe@fb.com>]

On 2014-04-10 00:45, Benjamin Herrenschmidt wrote:
> On Wed, 2014-04-09 at 21:52 -0600, Jens Axboe wrote:
>> On 2014-04-09 21:35, Benjamin Herrenschmidt wrote:
>>> On Wed, 2014-04-09 at 20:25 -0600, Jens Axboe wrote:
>>>> On 2014-04-09 19:36, Benjamin Herrenschmidt wrote:
>>>>> On Wed, 2014-04-09 at 19:31 -0600, Jens Axboe wrote:
>>>>>> OK, I think we're seeing different symptoms of the same bug. Stay
>>>>>> tuned, will have something for you to test shortly, I hope.
>>>>>
>>>>> Ah thanks. I'll defer the bisection then (it's painful on that machine
>>>>> for various reasons....)
>>>>
>>>> Can you try with these two patches applied?
>>>
>>> Booted to login prompt once ... and twice. Much better ! :-)
>>
>> Excellent! I was hoping it was the same bug :-)
>> I'll amend the commit and add your tested-by.
>
> A colleague was complaining of yet another oddball block related crash
> today on another machine when doing rsync's with upstream (this machine
> booted fine but crashed later on, but then it has less CPUs... maybe
> that's relevant) and these patches fixed it too.

I'm sure it could manifest itself in a lot of weird ways. I'll send it 
upstream this morning, so hopefully should be fixed in mainline shortly.

-- 
Jens Axboe