On 07/15/2013 05:05 PM, Rafael J. Wysocki wrote:
> On Monday, July 15, 2013 03:35:04 PM Srivatsa S. Bhat wrote:
>> On 07/15/2013 03:25 PM, Viresh Kumar wrote:
>>> Hi Srivatsa,
>>>
>>> I may be wrong but it looks something is wrong in this patch.
>>>
>>> On 12 July 2013 03:47, Srivatsa S. Bhat
>>> <srivatsa.b...@linux.vnet.ibm.com> wrote:
>>>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>>>
>>>> @@ -1239,29 +1263,40 @@ static int __cpufreq_remove_dev(struct device *dev,
>>>> if ((cpus == 1) && (cpufreq_driver->target))
>>>> __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
>>>>
>>>> - pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
>>>> - cpufreq_cpu_put(data);
>>>> + if (!frozen) {
>>>> + pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
>>>> + cpufreq_cpu_put(data);
>>>
>>> So, we don't decrement usage count here. But we are still increasing
>>> counts on cpufreq_add_dev after resume, isn't it?
>>>
>>> So, we wouldn't be able to free policy struct once all the cpus of a
>>> policy are removed after suspend/resume has happened once.
>>>
>>
>> Actually even I was wondering about this while writing the patch and
>> I even tested shutdown after multiple suspend/resume cycles, to verify that
>> the refcount is messed up. But surprisingly, things worked just fine.
>>
>> Logically there should've been a refcount mismatch and things should have
>> failed, but everything worked fine during my tests. Apart from suspend/resume
>> and shutdown tests, I even tried mixing a few regular CPU hotplug operations
>> (echo 0/1 to sysfs online files), but nothing stood out.
>>
>> Sorry, I forgot to document this in the patch. Either the patch is wrong
>> or something else is silently fixing this up. Not sure what is the exact
>> situation.
>
> OK, so I'm not going to queue [2-8/8] up until we find out what's going on
> here (and until Toralf tells me that it doesn't break his system any more).
>
Ok, that sounds good.
> I've queued up [1/8] for 3.11 already.
>
Thank you!
Regards,
Srivatsa S. Bhat
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