Commit a53b8394 authored by Javi Merino's avatar Javi Merino Committed by Eduardo Valentin
Browse files

thermal: cpu_cooling: fix out of bounds access in time_in_idle 



In __cpufreq_cooling_register() we allocate the arrays for time_in_idle
and time_in_idle_timestamp to be as big as the number of cpus in this
cpufreq device.  However, in get_load() we access this array using the
cpu number as index, which can result in an out of bound access.

Index time_in_idle{,_timestamp} using the index in the cpufreq_device's
allowed_cpus mask, as we do for the load_cpu array in
cpufreq_get_requested_power()

Reported-by: default avatarNicolas Boichat <drinkcat@chromium.org>
Cc: Amit Daniel Kachhap <amit.kachhap@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Tested-by: default avatarNicolas Boichat <drinkcat@chromium.org>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarJavi Merino <javi.merino@arm.com>
Signed-off-by: default avatarEduardo Valentin <edubezval@gmail.com>
parent 26716ce1

drivers/thermal/cpu_cooling.c

+8 −6
Original line number Diff line number Diff line
@@ -377,26 +377,28 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_device, 
 * get_load() - get load for a cpu since last updated

 * @cpufreq_device:	&struct cpufreq_cooling_device for this cpu

 * @cpu:	cpu number

 * @cpu_idx:	index of the cpu in cpufreq_device->allowed_cpus

 *

 * Return: The average load of cpu @cpu in percentage since this

 * function was last called.

 */

static u32 get_load(struct cpufreq_cooling_device *cpufreq_device, int cpu)

static u32 get_load(struct cpufreq_cooling_device *cpufreq_device, int cpu,

		    int cpu_idx)

{

	u32 load;

	u64 now, now_idle, delta_time, delta_idle;



	now_idle = get_cpu_idle_time(cpu, &now, 0);

	delta_idle = now_idle - cpufreq_device->time_in_idle[cpu];

	delta_time = now - cpufreq_device->time_in_idle_timestamp[cpu];

	delta_idle = now_idle - cpufreq_device->time_in_idle[cpu_idx];

	delta_time = now - cpufreq_device->time_in_idle_timestamp[cpu_idx];



	if (delta_time <= delta_idle)

		load = 0;

	else

		load = div64_u64(100 * (delta_time - delta_idle), delta_time);



	cpufreq_device->time_in_idle[cpu] = now_idle;

	cpufreq_device->time_in_idle_timestamp[cpu] = now;

	cpufreq_device->time_in_idle[cpu_idx] = now_idle;

	cpufreq_device->time_in_idle_timestamp[cpu_idx] = now;



	return load;

}
@@ -598,7 +600,7 @@ static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev, 
		u32 load;



		if (cpu_online(cpu))

			load = get_load(cpufreq_device, cpu);

			load = get_load(cpufreq_device, cpu, i);

		else

			load = 0;

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