Rafael J. Wysocki 0bf87fafc1 cpufreq: Reference count policy in cpufreq_update_limits()
commit 9e4e249018 upstream.

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: 5a25e3f7cc ("cpufreq: intel_pstate: Driver-specific handling of _PPC updates")
Closes: https://lore.kernel.org/linux-acpi/Z-ShAR59cTow0KcR@mail-itl
Reported-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>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/1928789.tdWV9SEqCh@rjwysocki.net
[do not use __free(cpufreq_cpu_put) in a backport]
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25 10:44:00 +02:00
2024-12-14 19:53:51 +01:00
2025-04-25 10:43:55 +02:00
2025-04-25 10:43:50 +02:00
2025-04-10 14:33:44 +02:00

Linux kernel
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There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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