linux-kernel - Re: [PATCH] hwmon: (coretemp) remove duplicated coretemp for same core id

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Date:   Wed, 18 Oct 2017 22:25:57 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Shu Wang <shuwang@...hat.com>
Cc:     fenghua yu <fenghua.yu@...el.com>, jdelvare@...e.com,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        chuhu@...hat.com, yizhan@...hat.com,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] hwmon: (coretemp) remove duplicated coretemp for same
 core id

On 10/18/2017 07:28 PM, Shu Wang wrote:
>> From: "Guenter Roeck" <linux@...ck-us.net>
>> To: "Shu Wang" <shuwang@...hat.com>
>> Cc: "fenghua yu" <fenghua.yu@...el.com>, jdelvare@...e.com, linux-hwmon@...r.kernel.org,
>> linux-kernel@...r.kernel.org, chuhu@...hat.com, yizhan@...hat.com
>> Sent: Wednesday, October 18, 2017 9:14:39 PM
>> Subject: Re: [PATCH] hwmon: (coretemp) remove duplicated coretemp for same core id
>>
>> On 10/17/2017 08:21 PM, Shu Wang wrote:
>>>> From: "Guenter Roeck" <linux@...ck-us.net>
>>>> To: shuwang@...hat.com
>>>> Cc: "fenghua yu" <fenghua.yu@...el.com>, jdelvare@...e.com,
>>>> linux-hwmon@...r.kernel.org,
>>>> linux-kernel@...r.kernel.org, chuhu@...hat.com, yizhan@...hat.com
>>>> Sent: Tuesday, October 17, 2017 11:25:50 PM
>>>> Subject: Re: [PATCH] hwmon: (coretemp) remove duplicated coretemp for same
>>>> core id
>>>>
>>>> On Tue, Oct 17, 2017 at 04:44:50PM +0800, shuwang@...hat.com wrote:
>>>>> From: Shu Wang <shuwang@...hat.com>
>>>>>
>>>>> Fix kernel warning on my 4cpus 2core_id system. The cpu0 and cpu1 have
>>>>> same core_id 0, so both cpu0 and cpu1 will try to create file temp2_label
>>>>> when it's online.
>>>>>
>>>> What system/cpu is that ?
>>>>
>>>> Normally I would assume that each CPU (package) instantiates
>>>> a separate instance of the driver.
>>>
>>> The system is ThinkPad X1 Carbon 3rd laptop, model 20BTS1N70F.
>>>
>>>>
>>>>> - coretemp_cpu_online(cpu=0)
>>>>>     - create_core_data(cpu=0, attr_no=2)
>>>>>      - create_core_attrs(attr_no=2)
>>>>> - coretemp_cpu_online(cpu=1)
>>>>>     - create_core_data(cpu=1, attr_no=2)
>>>>>      - create_core_attrs(attr_no=2)
>>>>>
>>>>> $ grep -e processor -e 'core id' /proc/cpuinfo
>>>>> processor       : 0
>>>>> core id         : 0
>>>>> processor       : 1
>>>>> core id         : 0
>>>>> processor       : 2
>>>>> core id         : 1
>>>>> processor       : 3
>>>>> core id         : 1
>>>>
>>>> Complete output of /proc/cpuinfo might be helpful.
>>>
>>> $ cat /proc/cpuinfo
>>> processor	: 0
>>> vendor_id	: GenuineIntel
>>> cpu family	: 6
>>> model		: 61
>>> model name	: Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
>>
>> This is a hyperthreading CPU, which should already be handled,
> 
> Do you mean that for my system, coretemp_cpu_online should only
> be called twice instead of four times to create two core attrs?
> 

coretemp_add_core() should only be called twice, and cpumask_intersects()
should filter out the duplicate ones.

         /*
          * Check whether a thread sibling is already online. If not add the
          * interface for this CPU core.
          */
         if (!cpumask_intersects(&pdata->cpumask, topology_sibling_cpumask(cpu)))
                 coretemp_add_core(pdev, cpu, 0);

Thomas, is it possible that something is wrong with this code ?

Guenter

>> and the problem would affect pretty much everyone. I'll have
>> to look into this more closely. Is this with the ToT kernel ?
> 
> What's a ToT kernel? The kernel I built was the latest
> kernel-4.14.0_rc5+ from linus repo.
> 

ToT => Top Of Tree. My apologies, I thought that was a commonly used acronym.

Guenter