From: Rafael J. Wysocki Date: Fri, 28 Mar 2025 20:39:08 +0000 (+0100) Subject: cpufreq: Reference count policy in cpufreq_update_limits() X-Git-Tag: v5.10.237~142 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e8c628ec2f611229175752b43446bac9817f3311;p=thirdparty%2Fkernel%2Fstable.git cpufreq: Reference count policy in cpufreq_update_limits() commit 9e4e249018d208678888bdf22f6b652728106528 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: 5a25e3f7cc53 ("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 Cc: All applicable Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 162de402b1134..d13139497da44 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2593,10 +2593,18 @@ 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);