Re: [Patch] Call sched_destroy_domain before cpupool_rm_domain.

[Juergen Gross <juergen.gross@ts.fujitsu.com>]

On 07.11.2013 10:37, Jan Beulich wrote:
>>>> On 07.11.13 at 10:09, Juergen Gross <juergen.gross@ts.fujitsu.com> wrote:
>> On 07.11.2013 08:39, Jan Beulich wrote:
>>>>>> On 05.11.13 at 06:59, Juergen Gross <juergen.gross@ts.fujitsu.com> wrote:
>>>> On 04.11.2013 16:22, Nate Studer wrote:
>>>>> On 11/4/2013 4:58 AM, Juergen Gross wrote:
>>>>>> All other schedulers will just call xfree() for the domain specific data
>> (and
>>>>>> may be update some statistic data, which is not critical).
>>>>>
>>>>> The credit and credit2 schedulers do a bit more than that in their
>> free_domdata
>>>>> functions.
>>>>
>>>> Sorry, got not enough sleep on the weekend ;-)
>>>>
>>>> I checked only 4.1 and 4.2 trees. There only xfree of the domain data is
>>>> done.
>>>>
>>>>>
>>>>> The credit scheduler frees the node_affinity_cpumask contained in the domain
>>>>> data and the credit2 scheduler deletes a list element contained in the
>> domain
>>>>> data.  Since with this bug they are accessing structures that do not belong
>> to
>>>>> them, bad things happen.
>>>>
>>>> So the patch would be subject to a 4.3 backport, I think.
>>>
>>> Hmm, I'm slightly confused: credit2's free_domdata has always been
>>> doing more than just xfree() afaict, and hence backporting is either
>>> necessary uniformly or (taking into account that it was made clear
>>> that arinc doesn't work with CPU pools anyway so far) not at all.
>>>
>>> Please clarify.
>>
>> Okay, I assumed only "production ready" features are to be taken into
>> account
>> for a backport. And credit2 is clearly not in this state, or am I wrong?
>
> You aren't, but is arinc production ready? I wouldn't think so
> simply based on it not working with CPU pools. And then the
> backporting question would become mute.

No, it doesn't. The following statement should have made that clear:

>> A 4.3 backport should be considered in any case, as sedf and credit
>> schedulers
>> behave differently in free_domdata, and both are "production ready".

If you have credit as default scheduler and use sedf in a cpupool, destroying
a domain in the cpupool with sedf will use the credit free_domdata routine,
leading to an error in 4.3 when calling free_cpumask_var().


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
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