Re: [PATCH v2] leds: pwm-multicolor: Manage the multi-led node reference

[Lee Jones <lee@kernel.org>]

On Fri, 30 Oct 2026, Yige Jiang wrote:

> led_pwm_mc_probe() leaks the multi-led node reference on successful
> probe and if the final PWM update fails. LED registration borrows
> the node, so it must remain valid until the LED is unregistered.
>
> Register a managed put action before LED registration. Reverse devres
> order then unregisters the LED before releasing the node on unbind
> or probe failure. Drop the manual error-path put and return directly
> on probe errors, leaving the reference cleanup to devres.
>
> Fixes: 9fa2762110dd ("leds: Add PWM multicolor driver")
> Assisted-by: LLM

I thought we dropped these now?

> Signed-off-by: Yige Jiang <yigejiang86@gmail.com>
> ---
> Changes in v2:
> - Capitalize the subject description to follow the LED subsystem style.
> - Remove the redundant release_mcnode label and return directly from
>   the probe error paths.
>
> v1: https://lore.kernel.org/r/rc-review-20261029-ai27-27-2c77ed65cec2@gmail.com
>
> Based on linux-next next-20261016 (2efb7a11f1aa).
> Compile-tested: arm64, GCC 14.2.0, W=1, CONFIG_OF_DYNAMIC=y.
> COMPILE_TEST=y.
> The object was rebuilt from this exact base with v2 applied.
> No full kernel or module-link, hardware or runtime test was performed.
>
>  drivers/leds/rgb/leds-pwm-multicolor.c | 31 +++++++++++++-------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/leds/rgb/leds-pwm-multicolor.c b/drivers/leds/rgb/leds-pwm-multicolor.c
> index 6365459ec27f17187804153cde6cb1805eca33e9..10527a64d1982733a43b76bd8bc123aba95b6f72 100644
> --- a/drivers/leds/rgb/leds-pwm-multicolor.c
> +++ b/drivers/leds/rgb/leds-pwm-multicolor.c
> @@ -106,6 +106,11 @@ release_fwnode:
>  	return ret;
>  }
>
> +static void led_pwm_mc_put_node(void *data)
> +{
> +	fwnode_handle_put(data);
> +}

What about?

    struct fwnode_handle *mcnode __free(fwnode_handle) =
        device_get_named_child_node(&pdev->dev, "multi-led");

> +
>  static int led_pwm_mc_probe(struct platform_device *pdev)
>  {
>  	struct fwnode_handle *mcnode;
> @@ -121,22 +126,22 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
>  		return dev_err_probe(&pdev->dev, -ENODEV,
>  				     "expected multi-led node\n");
>
> +	ret = devm_add_action_or_reset(&pdev->dev, led_pwm_mc_put_node, mcnode);
> +	if (ret)
> +		return ret;
> +
>  	/* count the nodes inside the multi-led node */
>  	count = fwnode_get_child_node_count(mcnode);
>
>  	priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
>  			    GFP_KERNEL);
> -	if (!priv) {
> -		ret = -ENOMEM;
> -		goto release_mcnode;
> -	}
> +	if (!priv)
> +		return -ENOMEM;
>  	mutex_init(&priv->lock);
>
>  	subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL);
> -	if (!subled) {
> -		ret = -ENOMEM;
> -		goto release_mcnode;
> -	}
> +	if (!subled)
> +		return -ENOMEM;
>  	priv->mc_cdev.subled_info = subled;
>
>  	/* init the multicolor's LED class device */
> @@ -144,14 +149,14 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
>  	ret = fwnode_property_read_u32(mcnode, "max-brightness",
>  				 &cdev->max_brightness);
>  	if (ret)
> -		goto release_mcnode;
> +		return ret;
>
>  	cdev->flags = LED_CORE_SUSPENDRESUME;
>  	cdev->brightness_set_blocking = led_pwm_mc_set;
>
>  	ret = iterate_subleds(&pdev->dev, priv, mcnode);
>  	if (ret)
> -		goto release_mcnode;
> +		return ret;
>
>  	init_data.fwnode = mcnode;
>  	ret = devm_led_classdev_multicolor_register_ext(&pdev->dev,
> @@ -161,7 +166,7 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
>  		dev_err(&pdev->dev,
>  			"failed to register multicolor PWM led for %s: %d\n",
>  			cdev->name, ret);
> -		goto release_mcnode;
> +		return ret;
>  	}
>
>  	ret = led_pwm_mc_set(cdev, cdev->brightness);
> @@ -172,10 +177,6 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
>
>  	platform_set_drvdata(pdev, priv);
>  	return 0;
> -
> -release_mcnode:
> -	fwnode_handle_put(mcnode);
> -	return ret;
>  }
>
>  static const struct of_device_id of_pwm_leds_mc_match[] = {
>
> base-commit: 2efb7a11f1aa4d2dc285fe2680cca22cb9f72f64
>

-- 
Lee Jones