[lvc-project] [PATCH v2] cpufreq: amd-pstate: add check for cpufreq_cpu_get's return value

[Yuan, Perry]

[AMD Official Use Only - AMD Internal Distribution Only]

> -----Original Message-----
> From: Anastasia Belova <abelova at astralinux.ru>
> Sent: Monday, August 26, 2024 9:39 PM
> To: Huang, Ray <Ray.Huang at amd.com>
> Cc: Anastasia Belova <abelova at astralinux.ru>; Shenoy, Gautham Ranjal
> <gautham.shenoy at amd.com>; Limonciello, Mario
> <Mario.Limonciello at amd.com>; Yuan, Perry <Perry.Yuan at amd.com>; Rafael J.
> Wysocki <rafael at kernel.org>; Viresh Kumar <viresh.kumar at linaro.org>; linux-
> pm at vger.kernel.org; linux-kernel at vger.kernel.org; lvc-
> project at linuxtesting.org
> Subject: [PATCH v2] cpufreq: amd-pstate: add check for cpufreq_cpu_get's
> return value
>
> 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>
> ---
> v2: remove mixing code and declarations
>  drivers/cpufreq/amd-pstate.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 68c616b572f2..f8d474168430 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -656,7 +656,12 @@ static void amd_pstate_adjust_perf(unsigned int
> cpu,
>       unsigned long max_perf, min_perf, des_perf,
>                     cap_perf, lowest_nonlinear_perf;
>       struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> -     struct amd_cpudata *cpudata = policy->driver_data;
> +     struct amd_cpudata *cpudata;
> +
> +     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);
> @@ -870,11 +875,16 @@ 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);
> -     struct amd_cpudata *cpudata = policy->driver_data;
> +     struct amd_cpudata *cpudata;
>       u32 prev_high = 0, cur_high = 0;
>       int ret;
>       bool highest_perf_changed = false;
>
> +     if (!policy)
> +             return;
> +
> +     cpudata = policy->driver_data;
> +
>       mutex_lock(&amd_pstate_driver_lock);
>       if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
>               goto free_cpufreq_put;
> --
> 2.30.2

Thanks for the fix, LGTM,

Reviewed-by: Perry Yuan <perry.yuan at amd.com>


Best Regards.

Perry.