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.
For the annotation to be correct, num_leds must reflect the number of allocated elements before leds[] is accessed. The driver already allocates space for device_get_child_node_count() elements up front, so set num_leds to that count right after allocation and fill the array by explicit index, instead of incrementing num_leds as each LED is added. No functional change intended. Signed-off-by: Mert Seftali <[email protected]> --- Build-tested only (also with FORTIFY_SOURCE and UBSAN_BOUNDS enabled). drivers/leds/leds-pwm.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index 6c1f2f50ff85..4c99a07da576 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, @@ -82,9 +82,10 @@ 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, - struct led_pwm *led, struct fwnode_handle *fwnode) + int idx, struct led_pwm *led, + struct fwnode_handle *fwnode) { - struct led_pwm_data *led_data = &priv->leds[priv->num_leds]; + struct led_pwm_data *led_data = &priv->leds[idx]; struct led_init_data init_data = { .fwnode = fwnode }; int ret; @@ -167,14 +168,13 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, } } - priv->num_leds++; return 0; } static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv) { struct led_pwm led; - int ret; + int ret, i = 0; device_for_each_child_node_scoped(dev, fwnode) { memset(&led, 0, sizeof(led)); @@ -193,7 +193,7 @@ 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, i++, &led, fwnode); if (ret) return ret; } @@ -217,6 +217,8 @@ static int led_pwm_probe(struct platform_device *pdev) if (!priv) return -ENOMEM; + priv->num_leds = count; + ret = led_pwm_create_fwnode(&pdev->dev, priv); if (ret) -- 2.54.0
