[PATCH] staging: vchiq_arm: Fix missing refcount decrement in error path for fw_node

[Javier Carrasco]

An error path was introduced without including the required call to
of_node_put() to decrement the node's refcount and avoid leaking memory.
If the call to kzalloc() for 'mgmt' fails, the probe returns without
decrementing the refcount.

Use the automatic cleanup facility to fix the bug and protect the code
against new error paths where the call to of_node_put() might be missing
again.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1c9e16b73166 ("staging: vc04_services: vchiq_arm: Split driver static and runtime data")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
---
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 27ceaac8f6cc..792cf3a807e1 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -1332,7 +1332,8 @@ MODULE_DEVICE_TABLE(of, vchiq_of_match);
 
 static int vchiq_probe(struct platform_device *pdev)
 {
-	struct device_node *fw_node;
+	struct device_node *fw_node __free(device_node) =
+		of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
 	const struct vchiq_platform_info *info;
 	struct vchiq_drv_mgmt *mgmt;
 	int ret;
@@ -1341,8 +1342,6 @@ static int vchiq_probe(struct platform_device *pdev)
 	if (!info)
 		return -EINVAL;
 
-	fw_node = of_find_compatible_node(NULL, NULL,
-					  "raspberrypi,bcm2835-firmware");
 	if (!fw_node) {
 		dev_err(&pdev->dev, "Missing firmware node\n");
 		return -ENOENT;
@@ -1353,7 +1352,6 @@ static int vchiq_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	mgmt->fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
-	of_node_put(fw_node);
 	if (!mgmt->fw)
 		return -EPROBE_DEFER;
 

---
base-commit: d61a00525464bfc5fe92c6ad713350988e492b88
change-id: 20241013-vchiq_arm-of_node_put-60a5eaaafd70

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