Re: Mysterious CFQ crash and RCU

From: Jens Axboe
Date: Wed May 25 2011 - 15:00:00 EST


On 2011-05-25 19:28, Paul Bolle wrote:
> On Wed, 2011-05-25 at 10:46 +0200, Jens Axboe wrote:
>> I don't think we are dealing with bad RCU usage in CFQ. My gut tells me
>> that this is related to the merging of cooperating queues. It fits
>> roughly with the time frame of when this issue started occuring, and
>> some of that reference logic looks fragile/racy.
>>
>> So if you _can_ test a patch easily, please try this one. It'll disable
>> that logic.
>
> I'm sorry, but with that patch (adapted to out previous discussion, so
> simply returning NULL) applied I still hit the same Oops:

No worries, it's still a data point. Back to the drawing board...

--
Jens Axboe

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