Commit b0142d66 authored Dec 10, 2019 by Rafael J. Wysocki

cpuidle: Fix cpuidle_driver_state_disabled()



It turns out that cpuidle_driver_state_disabled() can be called
before registering the cpufreq driver on some platforms, which
was not expected when it was introduced and which leads to a NULL
pointer dereference when trying to walk the CPUs associated with
the given cpuidle driver.

Fix the problem by making cpuidle_driver_state_disabled() check if
the driver's mask of CPUs associated with it is present and to set
CPUIDLE_FLAG_UNUSABLE for the given idle state in the driver's states
list if that is not the case to cause __cpuidle_register_device() to
set CPUIDLE_STATE_DISABLED_BY_DRIVER for that state for all cpuidle
devices registered by it later.

Fixes: cbda56d5 ("cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks")
Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 36fcb429

drivers/cpuidle/driver.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -403,6 +403,13 @@ void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,

		mutex_lock(&cpuidle_lock);

		spin_lock(&cpuidle_driver_lock);

		if (!drv->cpumask) {
		drv->states[idx].flags \|= CPUIDLE_FLAG_UNUSABLE;
		goto unlock;
		}

		for_each_cpu(cpu, drv->cpumask) {
		struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);

		@@ -415,5 +422,8 @@ void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
		dev->states_usage[idx].disable &= ~CPUIDLE_STATE_DISABLED_BY_DRIVER;
		}

		unlock:
		spin_unlock(&cpuidle_driver_lock);

		mutex_unlock(&cpuidle_lock);
		}

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