uacce: fix cdev handling in the cleanup path

When cdev_device_add fails, it internally releases the cdev memory,
and if cdev_device_del is then executed, it will cause a hang error.
To fix it, we check the return value of cdev_device_add() and clear
uacce->cdev to avoid calling cdev_device_del in the uacce_remove.

Fixes: 015d239 ("uacce: add uacce driver")
Cc: [email protected]
Signed-off-by: Wenkai Lin <[email protected]>
Signed-off-by: Chenghai Huang <[email protected]>
Acked-by: Zhangfei Gao <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: lin755

drivers/misc/uacce/uacce.c

@@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(uacce_alloc);
  */
 int uacce_register(struct uacce_device *uacce)
 {
+	int ret;
+
 	if (!uacce)
 		return -ENODEV;
 
@@ -529,7 +531,11 @@ int uacce_register(struct uacce_device *uacce)
 	uacce->cdev->ops = &uacce_fops;
 	uacce->cdev->owner = THIS_MODULE;
 
-	return cdev_device_add(uacce->cdev, &uacce->dev);
+	ret = cdev_device_add(uacce->cdev, &uacce->dev);
+	if (ret)
+		uacce->cdev = NULL;
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(uacce_register);