Re: [PATCH] cpufreq: amd-pstate: add check for cpufreq_cpu_get's return value

[Mario Limonciello <mario.limonciello@amd.com>]

On 6/3/2024 06:07, Anastasia Belova wrote:
> cpufreq_cpu_get may return NULL. To avoid NULL-dereference check it
> and return in case of error.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
Thank you!

Acked-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
>   drivers/cpufreq/amd-pstate.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 1b7e82a0ad2e..672cb6c280a4 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -621,6 +621,8 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
>   	unsigned long max_perf, min_perf, des_perf,
>   		      cap_perf, lowest_nonlinear_perf, max_freq;
>   	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> +	if (!policy)
> +		return;
>   	struct amd_cpudata *cpudata = policy->driver_data;
>   	unsigned int target_freq;
>   
> @@ -777,6 +779,8 @@ static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
>   static void amd_pstate_update_limits(unsigned int cpu)
>   {
>   	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> +	if (!policy)
> +		return;
>   	struct amd_cpudata *cpudata = policy->driver_data;
>   	u32 prev_high = 0, cur_high = 0;
>   	int ret;