[v9,3/7] leds: rgb: leds-ktd202x: Initialize mutex earlier

Commit Message

Hans de Goede May 4, 2024, 4:41 p.m. UTC

The mutex must be initialized before the LED class device is registered
otherwise there is a race where it may get used before it is initialized:

 DEBUG_LOCKS_WARN_ON(lock->magic != lock)
 WARNING: CPU: 2 PID: 2045 at kernel/locking/mutex.c:587 __mutex_lock
 ...
 RIP: 0010:__mutex_lock+0x7db/0xc10
 ...
 set_brightness_delayed_set_brightness.part.0+0x17/0x60
 set_brightness_delayed+0xf1/0x100
 process_one_work+0x222/0x5a0

Move the mutex_init() call earlier to avoid this race condition and
switch to devm_mutex_init() to avoid the need to add error-exit
cleanup to probe() if probe() fails later on.

Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
---
Changes in v9:
- Use devm_mutex_init() instead of plain mutex_init()

Changes in v8:
- New patch in v8 of this series
---
 drivers/leds/rgb/leds-ktd202x.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/leds/rgb/leds-ktd202x.c b/drivers/leds/rgb/leds-ktd202x.c
index 60ca6ec34336..d5c442163c46 100644
--- a/drivers/leds/rgb/leds-ktd202x.c
+++ b/drivers/leds/rgb/leds-ktd202x.c
@@ -556,6 +556,10 @@  static int ktd202x_probe(struct i2c_client *client)
 		return ret;
 	}
 
+	ret = devm_mutex_init(dev, &chip->mutex);
+	if (ret)
+		return ret;
+
 	chip->num_leds = (unsigned long)i2c_get_match_data(client);
 
 	chip->regulators[0].supply = "vin";
@@ -584,8 +588,6 @@  static int ktd202x_probe(struct i2c_client *client)
 		return ret;
 	}
 
-	mutex_init(&chip->mutex);
-
 	return 0;
 }
 
@@ -594,8 +596,6 @@  static void ktd202x_remove(struct i2c_client *client)
 	struct ktd202x *chip = i2c_get_clientdata(client);
 
 	ktd202x_chip_disable(chip);
-
-	mutex_destroy(&chip->mutex);
 }
 
 static void ktd202x_shutdown(struct i2c_client *client)