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Subject: Re: [PATCH] selftests: remove obsolete kconfig fragment for
 cpu-hotplug
To: Thomas Gleixner <tglx@linutronix.de>
Cc: lei.yang@windriver.com, linux-kselftest@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Shuah Khan <shuah@kernel.org>, Shuah Khan <shuahkh@osg.samsung.com>
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From: Shuah Khan <shuahkh@osg.samsung.com>
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Date: Wed, 1 Nov 2017 16:59:24 -0600
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On 11/01/2017 04:52 PM, Thomas Gleixner wrote:
> On Wed, 1 Nov 2017, Shuah Khan wrote:
>> On 10/17/2017 08:10 PM, lei.yang@windriver.com wrote:
>>> From: Lei Yang <Lei.Yang@windriver.com>
>>>
>>> Kconfig CONFIG_CPU_NOTIFIER_ERROR_INJECT has been removed since kernel 4.10
>>> check commit:
>>>     commit 530e9b76ae8f863dfdef4a6ad0b38613d32e8c3f
>>>     Author: Thomas Gleixner <tglx@linutronix.de>
>>>     Date:   Wed Dec 21 20:19:53 2016 +0100
>>>
>>>         cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions
>>>
>>>         hotcpu_notifier(), cpu_notifier(), __hotcpu_notifier(), __cpu_notifier(),
>>>         register_hotcpu_notifier(), register_cpu_notifier(),
>>>         __register_hotcpu_notifier(), __register_cpu_notifier(),
>>>         unregister_hotcpu_notifier(), unregister_cpu_notifier(),
>>>         __unregister_hotcpu_notifier(), __unregister_cpu_notifier()
>>>      <snip>
>>>
>>> Signed-off-by: Lei Yang <Lei.Yang@windriver.com>
>>> ---
>>>  tools/testing/selftests/cpu-hotplug/config | 1 -
>>>  1 file changed, 1 deletion(-)
>>>
>>> diff --git a/tools/testing/selftests/cpu-hotplug/config b/tools/testing/selftests/cpu-hotplug/config
>>> index e6ab090..d4aca2a 100644
>>> --- a/tools/testing/selftests/cpu-hotplug/config
>>> +++ b/tools/testing/selftests/cpu-hotplug/config
>>> @@ -1,2 +1 @@
>>>  CONFIG_NOTIFIER_ERROR_INJECTION=y
>>> -CONFIG_CPU_NOTIFIER_ERROR_INJECT=m
>>>
>>
>> Yes. It is removed from the kernel. However, selftests from the latest
>> release do get run routinely on older stable releases. Dropping the
>> config will impact coverage on older releases.
>>
>> Thomas/Greg,
>>
>> Any ideas on what we should do about this. On one hand it is a good idea
>> to remove it, however my concern is coverage on older releases.
> 
> Can you check the kernel version on which you are running and do it runtime
> conditionally?
> 

I have been avoiding adding kernel version checks to tests. Maybe this is
one exception since the functionality is obsoleted.

In any case, just removing the config isn't the complete solution. I will
have to think about this some.

thanks,
-- Shuah