Re: [PATCH v1 01/10] cpufreq: Reference count policy in cpufreq_update_limits()

Marek Marczykowski-Górecki
2025-04-15T13:08:22Z

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On Fri, Mar 28, 2025 at 09:39:08PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@invisiblethingslab.com>
> Cc: All applicable <stable@vger.kernel.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It looks like this patch is missing in stable branches.

> ---
> 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

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