thermal: bcm2835: Fix crash in bcm2835_thermal_debugfs

Phil Elwell · zhang-rui · commit 35122495a8c6 · 2019-03-18T22:11:06.000+08:00
"cat /sys/kernel/debug/bcm2835_thermal/regset" causes a NULL pointer dereference in bcm2835_thermal_debugfs. The driver makes use of the implementation details of the thermal framework to retrieve a pointer to its private data from a struct thermal_zone_device, and gets it wrong - leading to the crash. Instead, store its private data as the drvdata and retrieve the thermal_zone_device pointer from it. Fixes: bcb7dd9 ("thermal: bcm2835: add thermal driver for bcm2835 SoC") Signed-off-by: Phil Elwell <phil@raspberrypi.org> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
diff --git a/drivers/thermal/broadcom/bcm2835_thermal.c b/drivers/thermal/broadcom/bcm2835_thermal.c
@@ -119,8 +119,7 @@ static const struct debugfs_reg32 bcm2835_thermal_regs[] = {
 
 static void bcm2835_thermal_debugfs(struct platform_device *pdev)
 {
-	struct thermal_zone_device *tz = platform_get_drvdata(pdev);
-	struct bcm2835_thermal_data *data = tz->devdata;
+	struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
 	struct debugfs_regset32 *regset;
 
 	data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL);
@@ -266,7 +265,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 
 	data->tz = tz;
 
-	platform_set_drvdata(pdev, tz);
+	platform_set_drvdata(pdev, data);
 
 	/*
 	 * Thermal_zone doesn't enable hwmon as default,
@@ -290,8 +289,8 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 
 static int bcm2835_thermal_remove(struct platform_device *pdev)
 {
-	struct thermal_zone_device *tz = platform_get_drvdata(pdev);
-	struct bcm2835_thermal_data *data = tz->devdata;
+	struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
+	struct thermal_zone_device *tz = data->tz;
 
 	debugfs_remove_recursive(data->debugfsdir);
 	thermal_zone_of_sensor_unregister(&pdev->dev, tz);
