linux-kernel - [PATCH v2] char: xillybus: Fix error handling in xillybus_init

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Message-Id: <20250311013935.219615-1-make24@iscas.ac.cn>
Date: Tue, 11 Mar 2025 09:39:35 +0800
From: Ma Ke <make24@...as.ac.cn>
To: eli.billauer@...il.com,
	arnd@...db.de,
	gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH v2] char: xillybus: Fix error handling in xillybus_init_chrdev()

After cdev_alloc() succeed and cdev_add() failed, call cdev_del() to
remove unit->cdev from the system properly.

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 8cb5d216ab33 ("char: xillybus: Move class-related functions to new xillybus_class.c")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
Changes in v2:
- modified the patch as suggestions to avoid UAF.
---
 drivers/char/xillybus/xillybus_class.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
index c92a628e389e..356af6551b0d 100644
--- a/drivers/char/xillybus/xillybus_class.c
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -104,8 +104,7 @@ int xillybus_init_chrdev(struct device *dev,
 	if (rc) {
 		dev_err(dev, "Failed to add cdev.\n");
 		/* kobject_put() is normally done by cdev_del() */
-		kobject_put(&unit->cdev->kobj);
-		goto unregister_chrdev;
+		goto err_cdev;
 	}
 
 	for (i = 0; i < num_nodes; i++) {
@@ -157,6 +156,7 @@ int xillybus_init_chrdev(struct device *dev,
 		device_destroy(&xillybus_class, MKDEV(unit->major,
 						     i + unit->lowest_minor));
 
+err_cdev:
 	cdev_del(unit->cdev);
 
 unregister_chrdev:
-- 
2.25.1