workqueue: use put_device() instead of kfree()

BugLink: https://bugs.launchpad.net/bugs/1775771

[ Upstream commit 537f4146 ]

Never directly free @dev after calling device_register(), even
if it returned an error! Always use put_device() to give up the
reference initialized in this function instead.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

kernel/workqueue.c

@@ -5199,7 +5199,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
 
 	ret = device_register(&wq_dev->dev);
 	if (ret) {
-		kfree(wq_dev);
+		put_device(&wq_dev->dev);
 		wq->wq_dev = NULL;
 		return ret;
 	}