linux-kernel - Re: [PATCH] Fixes: 227942809b52 ("cpufreq: powernv: Restore cpu frequency to policy->cur on unthrottling")

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Message-Id: <30ee9ce2-b27b-785d-21bf-890047b4b64d@linux.ibm.com>
Date:   Mon, 16 Mar 2020 19:24:54 +0530
From:   Pratik Sampat <psampat@...ux.ibm.com>
To:     Daniel Axtens <dja@...ens.net>, linux-pm@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        pratik.r.sampat@...il.com, ego@...ux.vnet.ibm.com
Subject: Re: [PATCH] Fixes: 227942809b52 ("cpufreq: powernv: Restore cpu
 frequency to policy->cur on unthrottling")

Hi Daniel,

Sure thing I'll re-send them. Rookie mistake, my bad.
Thanks for pointing it out!

Regards,
Pratik

On 16/03/20 6:35 pm, Daniel Axtens wrote:
> Hi Pratik,
>
> Please could you resend this with a more meaningful subject line and
> move the Fixes: line to immediately above your signed-off-by?
>
> Thanks!
>
> Regards,
> Daniel
>
>> The patch avoids allocating cpufreq_policy on stack hence fixing frame
>> size overflow in 'powernv_cpufreq_work_fn'
>>
>> Signed-off-by: Pratik Rajesh Sampat <psampat@...ux.ibm.com>
>> ---
>>   drivers/cpufreq/powernv-cpufreq.c | 13 ++++++++-----
>>   1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
>> index 56f4bc0d209e..20ee0661555a 100644
>> --- a/drivers/cpufreq/powernv-cpufreq.c
>> +++ b/drivers/cpufreq/powernv-cpufreq.c
>> @@ -902,6 +902,7 @@ static struct notifier_block powernv_cpufreq_reboot_nb = {
>>   void powernv_cpufreq_work_fn(struct work_struct *work)
>>   {
>>   	struct chip *chip = container_of(work, struct chip, throttle);
>> +	struct cpufreq_policy *policy;
>>   	unsigned int cpu;
>>   	cpumask_t mask;
>>   
>> @@ -916,12 +917,14 @@ void powernv_cpufreq_work_fn(struct work_struct *work)
>>   	chip->restore = false;
>>   	for_each_cpu(cpu, &mask) {
>>   		int index;
>> -		struct cpufreq_policy policy;
>>   
>> -		cpufreq_get_policy(&policy, cpu);
>> -		index = cpufreq_table_find_index_c(&policy, policy.cur);
>> -		powernv_cpufreq_target_index(&policy, index);
>> -		cpumask_andnot(&mask, &mask, policy.cpus);
>> +		policy = cpufreq_cpu_get(cpu);
>> +		if (!policy)
>> +			continue;
>> +		index = cpufreq_table_find_index_c(policy, policy->cur);
>> +		powernv_cpufreq_target_index(policy, index);
>> +		cpumask_andnot(&mask, &mask, policy->cpus);
>> +		cpufreq_cpu_put(policy);
>>   	}
>>   out:
>>   	put_online_cpus();
>> -- 
>> 2.17.1