Commit e30952e4 authored Nov 29, 2017 by Ram Chandrasekar

drivers: thermal: Avoid race condition in updating the cooling device



Userspace when having a new request for cooling device, will use the
sysfs to vote. Since there can be a simultaneous request coming from
kernel governor, there is a potential race condition in updating the
update pending flag. This could leave a vote be ignored or delayed till
the next update.

Acquire mutex before updating the userspace request and the update
pending flag.

Change-Id: I41c86b92a21c42ecefe1127268958916c3bb5894
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>

parent d9f72f76

drivers/thermal/thermal_core.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1325,9 +1325,11 @@ thermal_cooling_device_cur_state_store(struct device *dev,
		if ((long)state < 0)
		return -EINVAL;

		mutex_lock(&cdev->lock);
		cdev->sysfs_cur_state_req = state;

		cdev->updated = false;
		mutex_unlock(&cdev->lock);
		thermal_cdev_update(cdev);

		return count;
		@@ -1349,9 +1351,11 @@ thermal_cooling_device_min_state_store(struct device *dev,
		if ((long)state < 0)
		return -EINVAL;

		mutex_lock(&cdev->lock);
		cdev->sysfs_min_state_req = state;

		cdev->updated = false;
		mutex_unlock(&cdev->lock);
		thermal_cdev_update(cdev);

		return count;