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From:   Parav Pandit <parav@mellanox.com>
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        kwankhede@nvidia.com, alex.williamson@redhat.com
Cc:     parav@mellanox.com
Subject: [PATCH 1/8] vfio/mdev: Fix to not do put_device on device_register failure
Date:   Fri, 22 Mar 2019 18:20:28 -0500
Message-Id: <1553296835-37522-2-git-send-email-parav@mellanox.com>
In-Reply-To: <1553296835-37522-1-git-send-email-parav@mellanox.com>
References: <1553296835-37522-1-git-send-email-parav@mellanox.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

device_register() performs put_device() if device_add() fails.
This balances with device_initialize().

mdev core performing put_device() when device_register() fails,
is an error that puts already released device again.
Therefore, don't put the device on error.

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Signed-off-by: Parav Pandit <parav@mellanox.com>
---
 drivers/vfio/mdev/mdev_core.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 0212f0e..3e5880a 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -318,10 +318,8 @@ int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
 	dev_set_name(&mdev->dev, "%pUl", uuid.b);
 
 	ret = device_register(&mdev->dev);
-	if (ret) {
-		put_device(&mdev->dev);
+	if (ret)
 		goto mdev_fail;
-	}
 
 	ret = mdev_device_create_ops(kobj, mdev);
 	if (ret)
-- 
1.8.3.1