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

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Message-ID: <Z6nacnX/CcynO2Cv@BLRRASHENOY1.amd.com>
Date: Mon, 10 Feb 2025 16:22:34 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
Cc: mario.limonciello@....com, rafael@...nel.org, viresh.kumar@...aro.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 09/12] cpufreq/amd-pstate: Fix cpufreq_policy ref counting

On Wed, Feb 05, 2025 at 11:25:20AM +0000, 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 for fixing this.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>

-- 
Thanks and Regards
gautham.

> ---
>  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);
> -- 
> 2.34.1
>