linux-kernel - [PATCH] As the doc of of_parse_phandle() states: "The device_node pointer with refcount incremented. Use * of_node

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Message-Id: <20250903140035.2529812-1-linmq006@gmail.com>
Date: Wed,  3 Sep 2025 22:00:35 +0800
From: Miaoqian Lin <linmq006@...il.com>
To: Thomas Zimmermann <tzimmermann@...e.de>,
	Javier Martinez Canillas <javierm@...hat.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Thierry Reding <treding@...dia.com>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Cc: linmq006@...il.com,
	stable@...r.kernel.org
Subject: [PATCH] As the doc of of_parse_phandle() states: "The device_node pointer with refcount incremented.  Use  * of_node_put() on it when done."

The function doesn't calls
of_node_put() to release this reference, causing a reference leak.

Move the of_parse_phandle() call after devm_kzalloc() and add the missing
of_node_put() call immediately after of_address_to_resource() to properly
release the device node reference.

Found via static analysis.

Fixes: 9a10c7e6519b ("drm/simpledrm: Add support for system memory framebuffers")
Cc: stable@...r.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@...il.com>
---
 drivers/gpu/drm/sysfb/simpledrm.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/sysfb/simpledrm.c b/drivers/gpu/drm/sysfb/simpledrm.c
index 8530a3ef8a7a..f0bd7e958398 100644
--- a/drivers/gpu/drm/sysfb/simpledrm.c
+++ b/drivers/gpu/drm/sysfb/simpledrm.c
@@ -183,15 +183,16 @@ simplefb_get_memory_of(struct drm_device *dev, struct device_node *of_node)
 	struct resource *res;
 	int err;
 
-	np = of_parse_phandle(of_node, "memory-region", 0);
-	if (!np)
-		return NULL;
-
 	res = devm_kzalloc(dev->dev, sizeof(*res), GFP_KERNEL);
 	if (!res)
 		return ERR_PTR(-ENOMEM);
 
+	np = of_parse_phandle(of_node, "memory-region", 0);
+	if (!np)
+		return NULL;
+
 	err = of_address_to_resource(np, 0, res);
+	of_node_put(np);
 	if (err)
 		return ERR_PTR(err);
 
-- 
2.35.1