[PATCH] leds: pwm-multicolor: manage the multi-led node reference

[PATCH] leds: pwm-multicolor: manage the multi-led node reference

[Yige Jiang]

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. Remove the explicit error-path put to avoid
releasing the reference twice.

Fixes: 9fa2762110dd ("leds: Add PWM multicolor driver")
Assisted-by: LLM
Signed-off-by: Yige Jiang <yigejiang86@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 built from this exact base with the patch applied.
No full kernel or module-link, hardware or runtime test was performed.

 drivers/leds/rgb/leds-pwm-multicolor.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/rgb/leds-pwm-multicolor.c b/drivers/leds/rgb/leds-pwm-multicolor.c
index 6365459ec27f17187804153cde6cb1805eca33e9..0ccf6839bc65f282f7c821e9fe7a50f431cc0d71 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);
+}
+
 static int led_pwm_mc_probe(struct platform_device *pdev)
 {
 	struct fwnode_handle *mcnode;
@@ -121,6 +126,10 @@ 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);
 
@@ -174,7 +183,6 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
 	return 0;
 
 release_mcnode:
-	fwnode_handle_put(mcnode);
 	return ret;
 }
 

base-commit: 2efb7a11f1aa4d2dc285fe2680cca22cb9f72f64

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

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Low] leds: pwm-multicolor: lowercase commit subject description
- [Low] leds: pwm-multicolor: unused release_mcnode label in led_pwm_mc_probe()
--

commit 67921ff7042ba5bbedd0da0b44a4a770d241be02
Author: Yige Jiang <yigejiang86@gmail.com>

leds: pwm-multicolor: manage the multi-led node reference

This commit registers a devm action in led_pwm_mc_probe() to release the
multi-led fwnode reference upon driver unbind or probe failure, and removes
the manual fwnode_handle_put() call on the error path.

>     leds: pwm-multicolor: manage the multi-led node reference
>     
>     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. Remove the explicit error-path put to avoid
>     releasing the reference twice.
>     
>     Fixes: 9fa2762110dd ("leds: Add PWM multicolor driver")
>     Assisted-by: LLM
>     Signed-off-by: Yige Jiang <yigejiang86@gmail.com>

[Severity: Low]
Should the commit subject description after the subsystem and driver prefix
be capitalized to follow the LED subsystem convention:

  leds: pwm-multicolor: Manage the multi-led node reference

> diff --git a/drivers/leds/rgb/leds-pwm-multicolor.c b/drivers/leds/rgb/leds-pwm-multicolor.c
> index 6365459ec27f1..0ccf6839bc65f 100644
> --- a/drivers/leds/rgb/leds-pwm-multicolor.c
> +++ b/drivers/leds/rgb/leds-pwm-multicolor.c

[ ... ]

> @@ -121,6 +126,10 @@ 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);
>  
> @@ -174,7 +183,6 @@ static int led_pwm_mc_probe(struct platform_device *pdev)
>  	return 0;
>  
>  release_mcnode:
> -	fwnode_handle_put(mcnode);
>  	return ret;
>  }

[Severity: Low]
In led_pwm_mc_probe() in drivers/leds/rgb/leds-pwm-multicolor.c, now that
fwnode_handle_put(mcnode) is registered via devm_add_action_or_reset() and
removed from the release_mcnode label, the release_mcnode label only executes
return ret.

Could the release_mcnode label and the goto release_mcnode jumps on the
subsequent error paths in led_pwm_mc_probe() be removed in favor of returning
directly?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/rc-review-20261029-ai27-27-2c77ed65cec2@gmail.com?part=1