thermal/core: Protect thermal device operations against thermal device removal

Thermal device operations may be called after thermal zone device removal.
After thermal zone device removal, thermal zone device operations must
no longer be called. To prevent such calls from happening, ensure that
the thermal device is registered before executing any thermal device
operations.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/thermal/thermal_core.c

@@ -203,6 +203,9 @@ int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
 	mutex_lock(&thermal_governor_lock);
 	mutex_lock(&tz->lock);
 
+	if (!device_is_registered(&tz->device))
+		goto exit;
+
 	gov = __find_governor(strim(policy));
 	if (!gov)
 		goto exit;
@@ -445,6 +448,12 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 		return ret;
 	}
 
+	if (!device_is_registered(&tz->device)) {
+		mutex_unlock(&tz->lock);
+
+		return -ENODEV;
+	}
+
 	if (tz->ops->change_mode)
 		ret = tz->ops->change_mode(tz, mode);
 
@@ -486,7 +495,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz,
 				enum thermal_notify_event event)
 {
 	mutex_lock(&tz->lock);
-	__thermal_zone_device_update(tz, event);
+	if (device_is_registered(&tz->device))
+		__thermal_zone_device_update(tz, event);
 	mutex_unlock(&tz->lock);
 }
 EXPORT_SYMBOL_GPL(thermal_zone_device_update);