From: Mert Seftali <[email protected]> Add the __counted_by() attribute to the flexible array member leds[] in struct led_pwm_priv so the compiler and runtime (e.g. FORTIFY_SOURCE, UBSAN_BOUNDS) can bounds-check accesses against num_leds.
While here, pass the led_pwm_data element into led_pwm_add() instead of the whole led_pwm_priv, so the helper no longer needs to index the array itself. num_leds is incremented in the caller as each LED is added and doubles as the index. No functional change intended. Suggested-by: Lee Jones <[email protected]> Signed-off-by: Mert Seftali <[email protected]> --- Changes in v2 (per Lee Jones review): - Pass the led_pwm_data element into led_pwm_add() so it drops the priv and index arguments; increment num_leds in the caller, where it also serves as the array index. Build-tested only (also with FORTIFY_SOURCE and UBSAN_BOUNDS enabled). drivers/leds/leds-pwm.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index 6c1f2f50ff85..dabdf0423582 100644 --- a/drivers/leds/leds-pwm.c +++ b/drivers/leds/leds-pwm.c @@ -36,7 +36,7 @@ struct led_pwm_data { struct led_pwm_priv { int num_leds; - struct led_pwm_data leds[]; + struct led_pwm_data leds[] __counted_by(num_leds); }; static int led_pwm_set(struct led_classdev *led_cdev, @@ -81,10 +81,9 @@ static int led_pwm_default_brightness_get(struct fwnode_handle *fwnode, } __attribute__((nonnull)) -static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, +static int led_pwm_add(struct device *dev, struct led_pwm_data *led_data, struct led_pwm *led, struct fwnode_handle *fwnode) { - struct led_pwm_data *led_data = &priv->leds[priv->num_leds]; struct led_init_data init_data = { .fwnode = fwnode }; int ret; @@ -167,7 +166,6 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, } } - priv->num_leds++; return 0; } @@ -193,9 +191,10 @@ static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv) led.default_state = led_init_default_state_get(fwnode); - ret = led_pwm_add(dev, priv, &led, fwnode); + ret = led_pwm_add(dev, &priv->leds[priv->num_leds], &led, fwnode); if (ret) return ret; + priv->num_leds++; } return 0; -- 2.55.0
