linux-kernel - Re: [PATCH v1 2/3] cpufreq: Always enforce policy limits even without frequency table

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250904044812.cpadajrtz3mrz2ke@vireshk-i7>
Date: Thu, 4 Sep 2025 10:18:12 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Zihuan Zhang <zhangzihuan@...inos.cn>
Cc: "Rafael J . wysocki" <rafael@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	zhenglifeng <zhenglifeng1@...wei.com>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/3] cpufreq: Always enforce policy limits even
 without frequency table

On 04-09-25, 11:22, Zihuan Zhang wrote:
> Currently, cpufreq_frequency_table_verify() simply returns when the driver’s
> frequency table is missing (policy->freq_table == NULL).
> This means that cpufreq_verify_within_cpu_limits() is not invoked in such
> cases, leaving policy->min and policy->max unchecked.
> 
> Some cpufreq drivers handle this manually by calling
> cpufreq_verify_within_cpu_limits() even when no frequency table is present,
> in order to ensure the policy stays within CPU limits.
> 
> To avoid this inconsistency and potential misuse, make
> cpufreq_generic_frequency_table_verify() always call
> cpufreq_verify_within_cpu_limits(), regardless of whether policy->freq_table
> is available. This unifies the behavior across all drivers and makes the helper
> safe to use universally.
> 
> Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
> ---
>  drivers/cpufreq/freq_table.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
> index d5111ee56e38..f4b05dcc479b 100644
> --- a/drivers/cpufreq/freq_table.c
> +++ b/drivers/cpufreq/freq_table.c
> @@ -105,6 +105,7 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
>   */
>  int cpufreq_generic_frequency_table_verify(struct cpufreq_policy_data *policy)
>  {
> +	cpufreq_verify_within_cpu_limits(policy);

So if we have a freq-table, we will call this twice now. Why make it
bad for the existing users ?

And then the name of this function, it is all about freq-table. If it
isn't there, not sure we should call it at all.

>  	if (!policy->freq_table)
>  		return -ENODEV;
>  
> -- 
> 2.25.1

-- 
viresh