HID: hidraw: improve error handling in hidraw_init()

Several improvements in error handling:
- do not report success if alloc_chrdev_region() failed
- check for error code of cdev_add()
- use unregister_chrdev_region() instead of unregister_chrdev()
  if class_create() failed

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 3b6f7bf5a77e..7c47fc3f7b2b 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -559,21 +559,28 @@ int __init hidraw_init(void)
 
         if (result < 0) {
                 pr_warn("can't get major number\n");
-                result = 0;
                 goto out;
         }
 
         hidraw_class = class_create(THIS_MODULE, "hidraw");
         if (IS_ERR(hidraw_class)) {
                 result = PTR_ERR(hidraw_class);
-                unregister_chrdev(hidraw_major, "hidraw");
-                goto out;
+                goto error_cdev;
         }
 
         cdev_init(&hidraw_cdev, &hidraw_ops);
-        cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
+        result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
+        if (result < 0)
+                goto error_class;
+
 out:
         return result;
+
+error_class:
+        class_destroy(hidraw_class);
+error_cdev:
+        unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
+        goto out;
 }
 
 void hidraw_exit(void)