linux-kernel - Re: [PATCH] powercap: DTPM: Fix the missing cpufreq_cpu

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Message-ID: <972bf6bc-20ca-4588-bed0-c95b1b24c552@arm.com>
Date:   Wed, 6 Dec 2023 13:12:35 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        daniel.lezcano@...aro.org, stable@...r.kernel.org
Subject: Re: [PATCH] powercap: DTPM: Fix the missing cpufreq_cpu_put() calls



On 12/5/23 19:54, Rafael J. Wysocki wrote:
> On Fri, Dec 1, 2023 at 1:31 PM Lukasz Luba <lukasz.luba@....com> wrote:
>>
>> The policy returned by cpufreq_cpu_get() has to be released with
>> the help of cpufreq_cpu_put() to balance its kobject reference counter
>> properly.
>>
>> Add the missing calls to cpufreq_cpu_put() in the code.
>>
>> Fixes: 0aea2e4ec2a2 ("powercap/dtpm_cpu: Reset per_cpu variable in the release function")
>> Fixes: 0e8f68d7f048 ("powercap/drivers/dtpm: Add CPU energy model based support")
>> Cc: <stable@...r.kernel.org> # v5.10+
>> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
>> ---
>>   drivers/powercap/dtpm_cpu.c | 17 +++++++++++++----
>>   1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
>> index 45bb7e2849d7..aac278e162d9 100644
>> --- a/drivers/powercap/dtpm_cpu.c
>> +++ b/drivers/powercap/dtpm_cpu.c
>> @@ -152,6 +152,8 @@ static void pd_release(struct dtpm *dtpm)
>>          if (policy) {
>>                  for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
>>                          per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;
>> +
>> +               cpufreq_cpu_put(policy);
>>          }
>>
>>          kfree(dtpm_cpu);
>> @@ -204,12 +206,16 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
>>                  return 0;
>>
>>          pd = em_cpu_get(cpu);
>> -       if (!pd || em_is_artificial(pd))
>> -               return -EINVAL;
>> +       if (!pd || em_is_artificial(pd)) {
>> +               ret = -EINVAL;
>> +               goto release_policy;
>> +       }
>>
>>          dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
>> -       if (!dtpm_cpu)
>> -               return -ENOMEM;
>> +       if (!dtpm_cpu) {
>> +               ret = -ENOMEM;
>> +               goto release_policy;
>> +       }
>>
>>          dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
>>          dtpm_cpu->cpu = cpu;
>> @@ -231,6 +237,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
>>          if (ret)
>>                  goto out_dtpm_unregister;
>>
>> +       cpufreq_cpu_put(policy);
>>          return 0;
>>
>>   out_dtpm_unregister:
>> @@ -242,6 +249,8 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
>>                  per_cpu(dtpm_per_cpu, cpu) = NULL;
>>          kfree(dtpm_cpu);
>>
>> +release_policy:
>> +       cpufreq_cpu_put(policy);
>>          return ret;
>>   }
>>
>> --
> 
> Applied as 6.7-rc material with the Cc: stable tag fixed.
> 
> Thanks!
> 

Thank you Rafael!