[lvc-project] [PATCH 6.6 1/1] cpufreq: amd-pstate: add check for cpufreq_cpu_get's return value

[Anastasia Belova]

Just a friendly reminder.

Cc'ing Mario Limonciello and Gautham Ranjal Shenoy.

On 11/6/24 9:19 PM, Anastasia Belova wrote:
> From: Anastasia Belova <abelova at astralinux.ru>
>
> commit 5493f9714e4cdaf0ee7cec15899a231400cb1a9f upstream.
>
> 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 at astralinux.ru>
> Reviewed-by: Perry Yuan <perry.yuan at amd.com>
> Signed-off-by: Viresh Kumar <viresh.kumar at linaro.org>
> ---
>   drivers/cpufreq/amd-pstate.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 8c16d67b98bf..0fc5495c935a 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -579,9 +579,14 @@ 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);
> -	struct amd_cpudata *cpudata = policy->driver_data;
> +	struct amd_cpudata *cpudata;
>   	unsigned int target_freq;
>   
> +	if (!policy)
> +		return;
> +
> +	cpudata = policy->driver_data;
> +
>   	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
>   		amd_pstate_update_min_max_limit(policy);
>