Commit c72e455b authored by Manuel Fombuena's avatar Manuel Fombuena Committed by Lee Jones
Browse files

leds: leds-st1202: Fix NULL pointer access on race condition 



st1202_dt_init() calls devm_led_classdev_register_ext() before the
internal data structures are properly set up, so the LEDs become visible
to user space while being partially initialized, leading to a window
where trying to access them causes a NULL pointer access.

Move devm_led_classdev_register_ext() from DT initialization
to the end of the probe function when DT and hardware are fully
initialized and ready to interact with user space.

Fixes: 25923037 ("leds: Add LED1202 I2C driver")
Signed-off-by: default avatarManuel Fombuena <fombuena@outlook.com>
Link: https://lore.kernel.org/r/CWLP123MB54732771AC0CE5491B3C84DCC5C32@CWLP123MB5473.GBRP123.PROD.OUTLOOK.COM


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent 2014c95a

drivers/leds/leds-st1202.c

+10 −11
Original line number Diff line number Diff line
@@ -261,8 +261,6 @@ static int st1202_dt_init(struct st1202_chip *chip) 
	int err, reg;



	for_each_available_child_of_node_scoped(dev_of_node(dev), child) {

		struct led_init_data init_data = {};



		err = of_property_read_u32(child, "reg", &reg);

		if (err)

			return dev_err_probe(dev, err, "Invalid register\n");
@@ -276,15 +274,6 @@ static int st1202_dt_init(struct st1202_chip *chip) 
		led->led_cdev.pattern_set = st1202_led_pattern_set;

		led->led_cdev.pattern_clear = st1202_led_pattern_clear;

		led->led_cdev.default_trigger = "pattern";



		init_data.fwnode = led->fwnode;

		init_data.devicename = "st1202";

		init_data.default_label = ":";



		err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data);

		if (err < 0)

			return dev_err_probe(dev, err, "Failed to register LED class device\n");



		led->led_cdev.brightness_set = st1202_brightness_set;

		led->led_cdev.brightness_get = st1202_brightness_get;

	}
@@ -368,6 +357,7 @@ static int st1202_probe(struct i2c_client *client) 
		return ret;



	for (int i = 0; i < ST1202_MAX_LEDS; i++) {

		struct led_init_data init_data = {};

		led = &chip->leds[i];

		led->chip = chip;

		led->led_num = i;
@@ -384,6 +374,15 @@ static int st1202_probe(struct i2c_client *client) 
		if (ret < 0)

			return dev_err_probe(&client->dev, ret,

					"Failed to clear LED pattern\n");



		init_data.fwnode = led->fwnode;

		init_data.devicename = "st1202";

		init_data.default_label = ":";



		ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data);

		if (ret < 0)

			return dev_err_probe(&client->dev, ret,

					"Failed to register LED class device\n");

	}



	return 0;