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Commit a305a438 authored by Brendan Jackman's avatar Brendan Jackman Committed by Zhang Rui
Browse files

thermal: cpu_cooling: Fix NULL dereference in cpufreq_state2power 



Currently all CPU cooling devices share a
`struct thermal_cooling_device_ops` instance. The thermal core uses the
presence of functions in this struct to determine if a cooling device
has a power model (see cdev_is_power_actor). cpu_cooling.c adds the
power model functions to the shared struct when a device is registered
with a power model.

Therefore, if a CPU cooling device is registered using
[of_]cpufreq_power_cooling_register, _all_ devices will be determined to
have a power model, including any registered with
[of_]cpufreq_cooling_register. This can result in cpufreq_state2power
being called on a device where dyn_power_table is NULL.

With this commit, instead of having a shared thermal_cooling_device_ops
which is mutated, we have two versions: one with the power functions and
one without.

Signed-off-by: default avatarBrendan Jackman <brendan.jackman@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Javi Merino <javi.merino@arm.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Acked-by: default avatarJavi Merino <javi.merino@arm.com>
Signed-off-by: default avatarZhang Rui <rui.zhang@intel.com>
parent 694d0d0b

drivers/thermal/cpu_cooling.c

+16 −5
Original line number Diff line number Diff line
@@ -740,12 +740,22 @@ static int cpufreq_power2state(struct thermal_cooling_device *cdev, 
}



/* Bind cpufreq callbacks to thermal cooling device ops */



static struct thermal_cooling_device_ops cpufreq_cooling_ops = {

	.get_max_state = cpufreq_get_max_state,

	.get_cur_state = cpufreq_get_cur_state,

	.set_cur_state = cpufreq_set_cur_state,

};



static struct thermal_cooling_device_ops cpufreq_power_cooling_ops = {

	.get_max_state		= cpufreq_get_max_state,

	.get_cur_state		= cpufreq_get_cur_state,

	.set_cur_state		= cpufreq_set_cur_state,

	.get_requested_power	= cpufreq_get_requested_power,

	.state2power		= cpufreq_state2power,

	.power2state		= cpufreq_power2state,

};



/* Notifier for cpufreq policy change */

static struct notifier_block thermal_cpufreq_notifier_block = {

	.notifier_call = cpufreq_thermal_notifier,
@@ -795,6 +805,7 @@ __cpufreq_cooling_register(struct device_node *np, 
	struct cpumask temp_mask;

	unsigned int freq, i, num_cpus;

	int ret;

	struct thermal_cooling_device_ops *cooling_ops;



	cpumask_and(&temp_mask, clip_cpus, cpu_online_mask);

	policy = cpufreq_cpu_get(cpumask_first(&temp_mask));
@@ -850,10 +861,6 @@ __cpufreq_cooling_register(struct device_node *np, 
	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);



	if (capacitance) {

		cpufreq_cooling_ops.get_requested_power =

			cpufreq_get_requested_power;

		cpufreq_cooling_ops.state2power = cpufreq_state2power;

		cpufreq_cooling_ops.power2state = cpufreq_power2state;

		cpufreq_dev->plat_get_static_power = plat_static_func;



		ret = build_dyn_power_table(cpufreq_dev, capacitance);
@@ -861,6 +868,10 @@ __cpufreq_cooling_register(struct device_node *np, 
			cool_dev = ERR_PTR(ret);

			goto free_table;

		}



		cooling_ops = &cpufreq_power_cooling_ops;

	} else {

		cooling_ops = &cpufreq_cooling_ops;

	}



	ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
@@ -885,7 +896,7 @@ __cpufreq_cooling_register(struct device_node *np, 
		 cpufreq_dev->id);



	cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,

						      &cpufreq_cooling_ops);

						      cooling_ops);

	if (IS_ERR(cool_dev))

		goto remove_idr;