[PATCH 0/2] leds: max5970: fix unreleased fwnode_handle in probe function

[PATCH 0/2] leds: max5970: fix unreleased fwnode_handle in probe function

[Javier Carrasco]

This series fixes the wrong management of the 'led_node' fwnode_handle,
which is not released after it is no longer required. This affects both
the normal path of execution and the existing error paths (currently
two) in max5970_led_probe().

First, the missing callst to fwnode_handle_put() in the different code
paths are added, to make the patch available for stable kernels. Then,
the code gets updated to a more robust approach by means of the __free()
macro to automatically release the node when it goes out of scope,
removing the need for explicit calls to fwnode_handle_put().

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
---
Javier Carrasco (2):
      leds: max5970: fix unreleased fwnode_handle in probe function
      leds: max5970: use cleanup facility for fwnode_handle led_node

 drivers/leds/leds-max5970.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
base-commit: f2493655d2d3d5c6958ed996b043c821c23ae8d3
change-id: 20241019-max5970-of_node_put-939b004f57d2

Best regards,
-- 
Javier Carrasco <javier.carrasco.cruz@gmail.com>

[PATCH 1/2] leds: max5970: fix unreleased fwnode_handle in probe function

[Javier Carrasco]

An object initialized via device_get_named_child_node() requires calls
to fwnode_handle_put() when it is no longer required to avoid leaking
memory.

Add the missing calls to fwnode_handle_put() in the different paths
(error paths and normal exit).

Cc: stable@vger.kernel.org
Fixes: 736214b4b02a ("leds: max5970: Add support for max5970")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
---
 drivers/leds/leds-max5970.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/leds/leds-max5970.c b/drivers/leds/leds-max5970.c
index 56a584311581..c021330e0ae7 100644
--- a/drivers/leds/leds-max5970.c
+++ b/drivers/leds/leds-max5970.c
@@ -72,6 +72,7 @@ static int max5970_led_probe(struct platform_device *pdev)
 
 		ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
 		if (!ddata) {
+			fwnode_handle_put(led_node);
 			fwnode_handle_put(child);
 			return -ENOMEM;
 		}
@@ -89,11 +90,14 @@ static int max5970_led_probe(struct platform_device *pdev)
 
 		ret = devm_led_classdev_register(dev, &ddata->cdev);
 		if (ret < 0) {
+			fwnode_handle_put(led_node);
 			fwnode_handle_put(child);
 			return dev_err_probe(dev, ret, "Failed to initialize LED %u\n", reg);
 		}
 	}
 
+	fwnode_handle_put(led_node);
+
 	return ret;
 }
 

-- 
2.43.0

[PATCH 2/2] leds: max5970: use cleanup facility for fwnode_handle led_node

[Javier Carrasco]

Add the automatic cleanup facility for 'led_node' to simplify the code
and make it more robust against new error paths where omitting a call to
fwnode_handle_put() would leak memory.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
---
 drivers/leds/leds-max5970.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/leds-max5970.c b/drivers/leds/leds-max5970.c
index c021330e0ae7..285074c53b23 100644
--- a/drivers/leds/leds-max5970.c
+++ b/drivers/leds/leds-max5970.c
@@ -45,7 +45,7 @@ static int max5970_led_set_brightness(struct led_classdev *cdev,
 
 static int max5970_led_probe(struct platform_device *pdev)
 {
-	struct fwnode_handle *led_node, *child;
+	struct fwnode_handle *child;
 	struct device *dev = &pdev->dev;
 	struct regmap *regmap;
 	struct max5970_led *ddata;
@@ -55,7 +55,8 @@ static int max5970_led_probe(struct platform_device *pdev)
 	if (!regmap)
 		return -ENODEV;
 
-	led_node = device_get_named_child_node(dev->parent, "leds");
+	struct fwnode_handle *led_node __free(fwnode_handle) =
+		device_get_named_child_node(dev->parent, "leds");
 	if (!led_node)
 		return -ENODEV;
 
@@ -72,7 +73,6 @@ static int max5970_led_probe(struct platform_device *pdev)
 
 		ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
 		if (!ddata) {
-			fwnode_handle_put(led_node);
 			fwnode_handle_put(child);
 			return -ENOMEM;
 		}
@@ -90,14 +90,11 @@ static int max5970_led_probe(struct platform_device *pdev)
 
 		ret = devm_led_classdev_register(dev, &ddata->cdev);
 		if (ret < 0) {
-			fwnode_handle_put(led_node);
 			fwnode_handle_put(child);
 			return dev_err_probe(dev, ret, "Failed to initialize LED %u\n", reg);
 		}
 	}
 
-	fwnode_handle_put(led_node);
-
 	return ret;
 }
 

-- 
2.43.0

Re: (subset) [PATCH 1/2] leds: max5970: fix unreleased fwnode_handle in probe function

[Lee Jones]

On Sat, 19 Oct 2024 21:36:43 +0200, Javier Carrasco wrote:
> An object initialized via device_get_named_child_node() requires calls
> to fwnode_handle_put() when it is no longer required to avoid leaking
> memory.
> 
> Add the missing calls to fwnode_handle_put() in the different paths
> (error paths and normal exit).
> 
> [...]

Applied, thanks!

[1/2] leds: max5970: fix unreleased fwnode_handle in probe function
      commit: 42c04062ba3cd1f2aef96dc160e0ab4b45b5e10a

--
Lee Jones [李琼斯]

Re: (subset) [PATCH 1/2] leds: max5970: fix unreleased fwnode_handle in probe function

[Lee Jones]

On Thu, 31 Oct 2024, Lee Jones wrote:

> On Sat, 19 Oct 2024 21:36:43 +0200, Javier Carrasco wrote:
> > An object initialized via device_get_named_child_node() requires calls
> > to fwnode_handle_put() when it is no longer required to avoid leaking
> > memory.
> > 
> > Add the missing calls to fwnode_handle_put() in the different paths
> > (error paths and normal exit).
> > 
> > [...]
> 
> Applied, thanks!
> 
> [1/2] leds: max5970: fix unreleased fwnode_handle in probe function
>       commit: 42c04062ba3cd1f2aef96dc160e0ab4b45b5e10a

Unapplied.

-- 
Lee Jones [李琼斯]

Re: [PATCH 2/2] leds: max5970: use cleanup facility for fwnode_handle led_node

[Lee Jones]

On Sat, 19 Oct 2024, Javier Carrasco wrote:

> Add the automatic cleanup facility for 'led_node' to simplify the code
> and make it more robust against new error paths where omitting a call to
> fwnode_handle_put() would leak memory.
> 
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
> ---
>  drivers/leds/leds-max5970.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)

This makes patch 1 completely pointless.

Please squash them and resubmit.

-- 
Lee Jones [李琼斯]