linux-kernel - [PATCH v2] of: unittest: Fix device reference count leak in of_unittest_pci_node

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Message-Id: <20250930081618.794-1-make24@iscas.ac.cn>
Date: Tue, 30 Sep 2025 16:16:18 +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,
	akpm@...ux-foundation.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH v2] 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. Add put_device() in the else
branch immediately after child_dev is no longer needed.

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

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 26409dd04589 ("of: unittest: Add pci_dt_testdrv pci driver")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
Changes in v2:
- modified the put_device() location as suggestions.
---
 drivers/of/unittest.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index e3503ec20f6c..388e9ec2cccf 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -4300,6 +4300,7 @@ static int of_unittest_pci_node_verify(struct pci_dev *pdev, bool add)
 		unittest(!np, "Child device tree node is not removed\n");
 		child_dev = device_find_any_child(&pdev->dev);
 		unittest(!child_dev, "Child device is not removed\n");
+		put_device(child_dev);
 	}

 failed:
-- 
2.17.1