On Fri, 19 Jun 2026, Mert Seftali wrote: > 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);
Nit, why not keep the variable names the same rather than use the for iterator? i's and j's are usually for throw-away variables, but this is counting something real. Or if you wanted to be even smarter, why not just pass the priv->leds[n] that you want to operate on and increment num_leds here instead? Less args == more better. > 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 > -- Lee Jones
