linux-kernel - Re: [PATCH v1 01/10] cpufreq: Reference count policy in cpufreq_update

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: <Z-dUm_z8daM_nQoy@mail-itl>
Date: Sat, 29 Mar 2025 03:02:01 +0100
From: Marek Marczykowski-Górecki <marmarek@...isiblethingslab.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Linux PM <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Mario Limonciello <mario.limonciello@....com>,
	Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH v1 01/10] cpufreq: Reference count policy in
 cpufreq_update_limits()

On Fri, Mar 28, 2025 at 09:39:08PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Since acpi_processor_notify() can be called before registering a cpufreq
> driver or even in cases when a cpufreq driver is not registered at all,
> cpufreq_update_limits() needs to check if a cpufreq driver is present
> and prevent it from being unregistered.
> 
> For this purpose, make it call cpufreq_cpu_get() to obtain a cpufreq
> policy pointer for the given CPU and reference count the corresponding
> policy object, if present.
> 
> Fixes: 5a25e3f7cc53 ("cpufreq: intel_pstate: Driver-specific handling of _PPC updates")
> Closes: https://lore.kernel.org/linux-acpi/Z-ShAR59cTow0KcR@mail-itl
> Reporetd-by: Marek Marczykowski-Górecki <marmarek@...isiblethingslab.com>

Reported

I wanted to propose also Tested-by tag, but technically it's not me who
tested it: https://forum.qubes-os.org/t/kernel-latest-6-13-6-boot-loop/32926/18

> Cc: All applicable <stable@...r.kernel.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/cpufreq/cpufreq.c |    6 ++++++
>  1 file changed, 6 insertions(+)
> 
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2781,6 +2781,12 @@
>   */
>  void cpufreq_update_limits(unsigned int cpu)
>  {
> +	struct cpufreq_policy *policy __free(put_cpufreq_policy);
> +
> +	policy = cpufreq_cpu_get(cpu);
> +	if (!policy)
> +		return;
> +
>  	if (cpufreq_driver->update_limits)
>  		cpufreq_driver->update_limits(cpu);
>  	else
> 
> 
> 

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)