Re: frequent lockups in 3.18rc4

From: Sasha Levin
Date: Sat Dec 13 2014 - 09:16:31 EST


On 12/13/2014 03:27 AM, Ingo Molnar wrote:
>
> * Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
>>
>> * Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>>
>>> On Fri, Dec 12, 2014 at 10:54 AM, Dave Jones <davej@xxxxxxxxxx> wrote:
>>>
>>>>
>>>> Something that's still making me wonder if it's some kind of
>>>> hardware problem is the non-deterministic nature of this bug.
>>>
>>> I'd expect it to be a race condition, though. Which can easily
>>> cause these kinds of issues, and the timing will be pretty
>>> random even if the load is very regular.
>>>
>>> And we know that the scheduler has an integer overflow under
>>> Sasha's loads, although I didn't hear anything from Ingo and
>>> friends about it. Ingo/Peter, you were cc'd on that report,
>>> where at least one of the multiplcations in wake_affine() ended
>>> up overflowing..
>>
>> Just to make sure, is there any other wake_affine report other
>> than the one in this thread? (I tried a wake_affine full text
>> search on my inbox and didn't find anything that appeared
>> relevant.)
>
> Found the report from Sasha:
>
> sched: odd values for effective load calculations
>
> right?

Yup, that's the one.


Thanks,
Sasha

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