Re: [PATCH wireless-next] wifi: rt2x00: Allocate LED names dynamically

[Stanislaw Gruszka]

Hi,

On Sun, May 17, 2026 at 04:17:59PM -0700, Rosen Penev wrote:
> The rt2x00 LED registration path builds LED class names from the
> driver and wiphy names. A fixed stack buffer can truncate those names
> before they are passed to the LED core.

To properly justify the change you'll need to provide real world
example when the size is not sufficient.

> Allocate each LED name with kasprintf(), check allocation failures, and
> release the stored name when the LED is unregistered.
> 
> Assisted-by: Codex:GPT-5.5
> Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
> ---
>  .../net/wireless/ralink/rt2x00/rt2x00leds.c   | 30 ++++++++++++++-----
>  1 file changed, 23 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00leds.c b/drivers/net/wireless/ralink/rt2x00/rt2x00leds.c
> index f5361d582d4e..8818e0b2447b 100644
> --- a/drivers/net/wireless/ralink/rt2x00/rt2x00leds.c
> +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00leds.c
> @@ -100,6 +100,8 @@ static int rt2x00leds_register_led(struct rt2x00_dev *rt2x00dev,
>  
>  	retval = led_classdev_register(device, &led->led_dev);
>  	if (retval) {
> +		kfree(name);
> +		led->led_dev.name = NULL;
>  		rt2x00_err(rt2x00dev, "Failed to register led handler\n");
>  		return retval;
>  	}
> @@ -111,15 +113,19 @@ static int rt2x00leds_register_led(struct rt2x00_dev *rt2x00dev,
>  
>  void rt2x00leds_register(struct rt2x00_dev *rt2x00dev)
>  {
> -	char name[36];
> +	char *name;
>  	int retval;
>  	unsigned long on_period;
>  	unsigned long off_period;
>  	const char *phy_name = wiphy_name(rt2x00dev->hw->wiphy);
>  
>  	if (rt2x00dev->led_radio.flags & LED_INITIALIZED) {
> -		snprintf(name, sizeof(name), "%s-%s::radio",
> -			 rt2x00dev->ops->name, phy_name);
> +		name = kasprintf(GFP_KERNEL, "%s-%s::radio",
> +				 rt2x00dev->ops->name, phy_name);
> +		if (!name) {
> +			retval = -ENOMEM;
> +			goto exit_fail;
> +		}

This is overengineering. If needed, the name size can be increased.

Regards
Stanislaw

>  
>  		retval = rt2x00leds_register_led(rt2x00dev,
>  						 &rt2x00dev->led_radio,
> @@ -129,8 +135,12 @@ void rt2x00leds_register(struct rt2x00_dev *rt2x00dev)
>  	}
>  
>  	if (rt2x00dev->led_assoc.flags & LED_INITIALIZED) {
> -		snprintf(name, sizeof(name), "%s-%s::assoc",
> -			 rt2x00dev->ops->name, phy_name);
> +		name = kasprintf(GFP_KERNEL, "%s-%s::assoc",
> +				 rt2x00dev->ops->name, phy_name);
> +		if (!name) {
> +			retval = -ENOMEM;
> +			goto exit_fail;
> +		}
>  
>  		retval = rt2x00leds_register_led(rt2x00dev,
>  						 &rt2x00dev->led_assoc,
> @@ -140,8 +150,12 @@ void rt2x00leds_register(struct rt2x00_dev *rt2x00dev)
>  	}
>  
>  	if (rt2x00dev->led_qual.flags & LED_INITIALIZED) {
> -		snprintf(name, sizeof(name), "%s-%s::quality",
> -			 rt2x00dev->ops->name, phy_name);
> +		name = kasprintf(GFP_KERNEL, "%s-%s::quality",
> +				 rt2x00dev->ops->name, phy_name);
> +		if (!name) {
> +			retval = -ENOMEM;
> +			goto exit_fail;
> +		}
>  
>  		retval = rt2x00leds_register_led(rt2x00dev,
>  						 &rt2x00dev->led_qual,
> @@ -182,6 +196,8 @@ static void rt2x00leds_unregister_led(struct rt2x00_led *led)
>  		led->led_dev.brightness_set(&led->led_dev, LED_OFF);
>  
>  	led->flags &= ~LED_REGISTERED;
> +	kfree(led->led_dev.name);
> +	led->led_dev.name = NULL;
>  }
>  
>  void rt2x00leds_unregister(struct rt2x00_dev *rt2x00dev)
> -- 
> 2.54.0
>