linux-kernel - Re: [PATCH 09/12] cpufreq/amd-pstate: Fix cpufreq

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Message-ID: <12f4ccea-f795-4c4d-818c-f28dbc5a3c5c@amd.com>
Date: Wed, 5 Feb 2025 11:48:14 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Dhananjay Ugwekar <dhananjay.ugwekar@....com>, gautham.shenoy@....com,
 rafael@...nel.org, viresh.kumar@...aro.org
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 09/12] cpufreq/amd-pstate: Fix cpufreq_policy ref counting

On 2/5/2025 05:25, Dhananjay Ugwekar wrote:
> amd_pstate_update_limits() takes a cpufreq_policy reference but doesn't
> decrement the refcount in one of the exit paths, fix that.
> 
> Fixes: 45722e777fd9 ("cpufreq: amd-pstate: Optimize amd_pstate_update_limits()")
> Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>

Thanks.

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

I'll queue this fix for 6.14-rc.
> ---
>   drivers/cpufreq/amd-pstate.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 107ad953ce43..9c939be59042 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -821,20 +821,21 @@ 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 cpufreq_policy *policy = NULL;
>   	struct amd_cpudata *cpudata;
>   	u32 prev_high = 0, cur_high = 0;
>   	int ret;
>   	bool highest_perf_changed = false;
>   
> +	if (!amd_pstate_prefcore)
> +		return;
> +
> +	policy = cpufreq_cpu_get(cpu);
>   	if (!policy)
>   		return;
>   
>   	cpudata = policy->driver_data;
>   
> -	if (!amd_pstate_prefcore)
> -		return;
> -
>   	guard(mutex)(&amd_pstate_driver_lock);
>   
>   	ret = amd_get_highest_perf(cpu, &cur_high);