2020-03-06 11:07:05

by Pratik R. Sampat

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

The patch avoids allocating cpufreq_policy on stack hence fixing frame
size overflow in 'powernv_cpufreq_work_fn'

Signed-off-by: Pratik Rajesh Sampat <[email protected]>
---
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

2020-03-16 13:06:43

by Daniel Axtens

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

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 <[email protected]>
> ---
> 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

2020-03-16 13:55:42

by Pratik R. Sampat

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 <[email protected]>
>> ---
>> 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