linux-kernel - [PATCH v3] char: xillybus: Fix error handling in xillybus_init

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Message-Id: <20250718100815.3404437-1-make24@iscas.ac.cn>
Date: Fri, 18 Jul 2025 18:08:15 +0800
From: Ma Ke <make24@...as.ac.cn>
To: eli.billauer@...il.com,
	arnd@...db.de,
	gregkh@...uxfoundation.org
Cc: akpm@...ux-foundation.org,
	linux-kernel@...r.kernel.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH v3] char: xillybus: Fix error handling in xillybus_init_chrdev()

Use cdev_del() instead of direct kobject_put() when cdev_add() fails.
This aligns with standard kernel practice and maintains consistency
within the driver's own error paths.

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 v3:
- modified the patch description, centralized cdev cleanup through standard API and maintained symmetry with driver's existing error handling;
Changes in v2:
- modified the patch as suggestions to avoid UAF.
---
 drivers/char/xillybus/xillybus_class.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
index c92a628e389e..e79cf9a0caa4 100644
--- a/drivers/char/xillybus/xillybus_class.c
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -103,8 +103,7 @@ int xillybus_init_chrdev(struct device *dev,
 		      unit->num_nodes);
 	if (rc) {
 		dev_err(dev, "Failed to add cdev.\n");
-		/* kobject_put() is normally done by cdev_del() */
-		kobject_put(&unit->cdev->kobj);
+		cdev_del(unit->cdev);
 		goto unregister_chrdev;
 	}
 
@@ -157,8 +156,6 @@ int xillybus_init_chrdev(struct device *dev,
 		device_destroy(&xillybus_class, MKDEV(unit->major,
 						     i + unit->lowest_minor));
 
-	cdev_del(unit->cdev);
-
 unregister_chrdev:
 	unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
 				 unit->num_nodes);
-- 
2.25.1