Re: [PATCH] cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_work_fn

From: Gautham R Shenoy
Date: Fri Mar 20 2020 - 06:38:05 EST


On Mon, Mar 16, 2020 at 07:27:43PM +0530, Pratik Rajesh Sampat wrote:
> The patch avoids allocating cpufreq_policy on stack hence fixing frame
> size overflow in 'powernv_cpufreq_work_fn'
>

Thanks for fixing this.

> Fixes: 227942809b52 ("cpufreq: powernv: Restore cpu frequency to policy->cur on unthrottling")
> Signed-off-by: Pratik Rajesh Sampat <psampat@xxxxxxxxxxxxx>

Reviewed-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>

> ---
> 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();
> --
> 2.24.1
>