Re: cpuidle regression ?

Daniel Lezcano
2019-12-09T17:22:21Z

On 09/12/2019 12:55, Rafael J. Wysocki wrote:
> On Mon, Dec 9, 2019 at 12:35 PM Daniel Lezcano
> <daniel.lezcano@linaro.org> wrote:
>>
>> On 09/12/2019 11:50, Rafael J. Wysocki wrote:
>>> On Mon, Dec 9, 2019 at 11:32 AM Daniel Lezcano
>>> <daniel.lezcano@linaro.org> wrote:
>>>>
>>>> On 09/12/2019 10:26, Rafael J. Wysocki wrote:
>>>>> On Sun, Dec 8, 2019 at 11:40 AM Daniel Lezcano
>>>>> <daniel.lezcano@linaro.org> wrote:
>>>>>>
>>>>>>
>>>>>> Hi Rafael,
>>>>>>
>>>>>> the latest linux-next kernelci report indicates a kernel bug for the
>>>>>> imx6 platform. I don't have this board so it is not possible to
>>>>>> investigate it.
>>>>>>
>>>>>> https://storage.kernelci.org/next/master/next-20191208/arm/multi_v7_defconfig/gcc-8/lab-collabora/boot-imx6q-sabrelite.html
>>>>>>
>>>>>> [ ... ]
>>>>>>
>>>>>> [ 3.372501] Unable to handle kernel NULL pointer dereference at
>>>>>> virtual address 00000000
>>>>>>
>>>>>> [ ... ]
>>>>>>
>>>>>> [ 3.408898] PC is at _find_first_bit_le+0xc/0x2c
>>>>>> [ 3.413785] LR is at cpuidle_driver_state_disabled+0x40/0xa0
>>>>>>
>>>>>>
>>>>>> Not sure if it is related to the latest changes or not.
>>>>>
>>>>> It does seem so, in which case the attached patch should address it.
>>>>>
>>>>> Is there a way to test the patch alone or do I need to push it
>>>>> somewhere to be tested?
>>>>
>>>> Is the bleeding-edge branch monitored by kernelci ?
>>>
>>> No, it is not right now, AFAICS.
>>
>> I have a imx7, I will try to reproduce the issue on it. Otherwise, I can
>> test on the 'testing' thermal branch temporarily.
>
> Thanks, that'll help!

The imx7 kernel has an issue with cpuidle but not related to your
changes, so I was unable to double check with a local board.

However, kernelci does no longer report a regression on the baseline
with your patch applied on my 'testing' branch.

I can not guarantee the bug is fixed because I can't reproduce it
locally and check the patch is effectively solving the issue.

In order to increase the confidence on the fix, I updated the branch
without your patch, so in a few hours, we should see the if the
regression appears or not.