linux-kernel - [PATCH] samples/vfio-mdev: don't return zero on failure paths in mtty_dev

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Date:   Sat, 31 Dec 2016 01:40:29 +0300
From:   Alexey Khoroshilov <khoroshilov@...ras.ru>
To:     Kirti Wankhede <kwankhede@...dia.com>, Neo Jia <cjia@...dia.com>
Cc:     Alexey Khoroshilov <khoroshilov@...ras.ru>,
        Alex Williamson <alex.williamson@...hat.com>,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        ldv-project@...uxtesting.org
Subject: [PATCH] samples/vfio-mdev: don't return zero on failure paths in mtty_dev_init()

If class_create() or mdev_register_device() fail, mtty_dev_init()
breaks off initialization, deallocates all resources, but returns zero.

The patch adds proper error code return values.

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

Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>
---
 samples/vfio-mdev/mtty.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 6b633a4ea333..e9c52e1f97a6 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1446,6 +1446,7 @@ static int __init mtty_dev_init(void)
 	mtty_dev.vd_class = class_create(THIS_MODULE, MTTY_CLASS_NAME);
 
 	if (IS_ERR(mtty_dev.vd_class)) {
+		ret = PTR_ERR(mtty_dev.vd_class);
 		pr_err("Error: failed to register mtty_dev class\n");
 		goto failed1;
 	}
@@ -1458,7 +1459,8 @@ static int __init mtty_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	if (mdev_register_device(&mtty_dev.dev, &mdev_fops) != 0)
+	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
+	if (ret)
 		goto failed3;
 
 	mutex_init(&mdev_list_lock);
@@ -1467,11 +1469,9 @@ static int __init mtty_dev_init(void)
 	goto all_done;
 
 failed3:
-
 	device_unregister(&mtty_dev.dev);
 failed2:
 	class_destroy(mtty_dev.vd_class);
-
 failed1:
 	cdev_del(&mtty_dev.vd_cdev);
 	unregister_chrdev_region(mtty_dev.vd_devt, MINORMASK);
-- 
2.7.4