linux-kernel - [PATCH] of: unittest: Fix device reference count leak in of_unittest_pci_node

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Message-Id: <20250920085135.21835-1-make24@iscas.ac.cn>
Date: Sat, 20 Sep 2025 16:51:35 +0800
From: Ma Ke <make24@...as.ac.cn>
To: robh@...nel.org,
	saravanak@...gle.com,
	lizhi.hou@....com
Cc: devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH] of: unittest: Fix device reference count leak in of_unittest_pci_node_verify

In of_unittest_pci_node_verify(), when the add parameter is false,
device_find_any_child() obtains a reference to a child device. This
function implicitly calls get_device() to increment the device's
reference count before returning the pointer. However, the caller
fails to properly release this reference by calling put_device(),
leading to a device reference count leak.

As the comment of device_find_any_child states: "NOTE: you will need
to drop the reference with put_device() after use".

Cc: stable@...r.kernel.org
Fixes: 26409dd04589 ("of: unittest: Add pci_dt_testdrv pci driver")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/of/unittest.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index e3503ec20f6c..d225e73781fe 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -4271,7 +4271,7 @@ static struct platform_driver unittest_pci_driver = {
 static int of_unittest_pci_node_verify(struct pci_dev *pdev, bool add)
 {
 	struct device_node *pnp, *np = NULL;
-	struct device *child_dev;
+	struct device *child_dev = NULL;
 	char *path = NULL;
 	const __be32 *reg;
 	int rc = 0;
@@ -4306,6 +4306,8 @@ static int of_unittest_pci_node_verify(struct pci_dev *pdev, bool add)
 	kfree(path);
 	if (np)
 		of_node_put(np);
+	if (child_dev)
+		put_device(child_dev);
 
 	return rc;
 }
-- 
2.17.1