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cpufreq: Reference count policy in cpufreq_update_limits()

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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>
This commit is contained in:
Rafael J. Wysocki
2025-03-28 21:39:08 +01:00
committed by Greg Kroah-Hartman
parent 7e2449ee66
commit 8c8d0e8000
1 changed files with 8 additions and 0 deletions
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drivers/cpufreq/cpufreq.c
+8
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@@ -2725,10 +2725,18 @@ EXPORT_SYMBOL(cpufreq_update_policy);
*/
void cpufreq_update_limits(unsigned int cpu)
{
struct cpufreq_policy *policy;
policy = cpufreq_cpu_get(cpu);
if (!policy)
return;
if (cpufreq_driver->update_limits)
cpufreq_driver->update_limits(cpu);
else
cpufreq_update_policy(cpu);
cpufreq_cpu_put(policy);
}
EXPORT_SYMBOL_GPL(cpufreq_update_limits);