linux-kernel - [PATCH] hwmon: (adt7475) Fix memory leak in adt7475_fan_pwm

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Message-Id: <20240926-hwmon_adt7475_memleak-v1-1-89b8ee07507a@gmail.com>
Date: Thu, 26 Sep 2024 11:38:11 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>, 
 Uwe Kleine-König <ukleinek@...nel.org>, 
 Chris Packham <chris.packham@...iedtelesis.co.nz>
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-pwm@...r.kernel.org, Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH] hwmon: (adt7475) Fix memory leak in
 adt7475_fan_pwm_config()

The device_for_each_child_node() loop requires calls to
fwnode_handle_put() upon early returns to decrement the refcount of
the child node and avoid leaking memory.

There are multiple early returns within that loop in
adt7475_fan_pwm_config(), but fwnode_handle_put() is never called.
Instead of adding the missing calls, the scoped version of the loop can
be used to simplify the code and avoid mistakes in the future if new
early returns are added.

This issue was recently introduced and it does not affect old kernels
that do not support the scoped variant.

Fixes: 777c97ff08d0 ("hwmon: (adt7475) Add support for configuring initial PWM state")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
 drivers/hwmon/adt7475.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index ca466d12475a..5f2541c11fe9 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -1735,11 +1735,10 @@ static int adt7475_pwm_properties_parse_args(struct fwnode_handle *fwnode,
 static int adt7475_fan_pwm_config(struct i2c_client *client)
 {
 	struct adt7475_data *data = i2c_get_clientdata(client);
-	struct fwnode_handle *child;
 	struct adt7475_pwm_config cfg = {};
 	int ret;
 
-	device_for_each_child_node(&client->dev, child) {
+	device_for_each_child_node_scoped(&client->dev, child) {
 		if (!fwnode_property_present(child, "pwms"))
 			continue;
 

---
base-commit: 92fc9636d1471b7f68bfee70c776f7f77e747b97
change-id: 20240926-hwmon_adt7475_memleak-36ef4edde4b8

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