linux-kernel - [PATCH] Input: Fix error handling in input_register

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Message-Id: <20250105092448.274424-1-make24@iscas.ac.cn>
Date: Sun,  5 Jan 2025 17:24:48 +0800
From: Ma Ke <make24@...as.ac.cn>
To: dmitry.torokhov@...il.com,
	jeff@...undy.com,
	bentiss@...nel.org
Cc: linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH] Input: Fix error handling in input_register_device()

When device_add(&dev->dev) failed, calling put_device() to explicitly
release dev->dev. Otherwise, it could cause double free problem.

As comment of device_add() says, if device_add() succeeds, you should
call device_del() when you want to get rid of it. If device_add() has
not succeeded, use only put_device() to drop the reference count.

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 0cd587735205 ("Input: preallocate memory to hold event values")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/input/input.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 7f0477e04ad2..a0a36aa90ecc 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -2456,8 +2456,10 @@ int input_register_device(struct input_dev *dev)
 		input_dev_poller_finalize(dev->poller);
 
 	error = device_add(&dev->dev);
-	if (error)
+	if (error) {
+		put_device(&dev->dev);
 		goto err_devres_free;
+	}
 
 	path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
 	pr_info("%s as %s\n",
-- 
2.25.1