linux-kernel - [PATCH] media: v4l2-dev: fix error handling in __video_register

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Message-Id: <20250313074318.305556-1-make24@iscas.ac.cn>
Date: Thu, 13 Mar 2025 15:43:18 +0800
From: Ma Ke <make24@...as.ac.cn>
To: mchehab@...nel.org,
	hverkuil@...all.nl,
	sakari.ailus@...ux.intel.com,
	viro@...iv.linux.org.uk,
	bartosz.golaszewski@...aro.org,
	make24@...as.ac.cn,
	benjamin.gaignard@...labora.com,
	hljunggr@...co.com
Cc: linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH] media: v4l2-dev: fix error handling in __video_register_device()

Once device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.

As comment of device_register() says, 'NOTE: _Never_ directly free
@dev after calling this function, even if it returned an error! Always
use put_device() to give up the reference initialized in this function
instead.'

Found by code review.

Cc: stable@...r.kernel.org
Fixes: baa057e29b58 ("media: v4l2-dev: use pr_foo() for printing messages")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/media/v4l2-core/v4l2-dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 5bcaeeba4d09..1619614e96bf 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -1060,6 +1060,7 @@ int __video_register_device(struct video_device *vdev,
 	if (ret < 0) {
 		mutex_unlock(&videodev_lock);
 		pr_err("%s: device_register failed\n", __func__);
+		put_device(&vdev->dev);
 		goto cleanup;
 	}
 	/* Register the release callback that will be called when the last
-- 
2.25.1