mISDN: fix possible memory leak in mISDN_register_device()

[ Upstream commit e7d1d4d ]

Afer commit 1fa5ae8 ("driver core: get rid of struct device's
bus_id string array"), the name of device is allocated dynamically,
add put_device() to give up the reference, so that the name can be
freed in kobject_cleanup() when the refcount is 0.

Set device class before put_device() to avoid null release() function
WARN message in device_release().

Fixes: 1fa5ae8 ("driver core: get rid of struct device's bus_id string array")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/isdn/mISDN/core.c

@@ -233,11 +233,12 @@ mISDN_register_device(struct mISDNdevice *dev,
 	if (debug & DEBUG_CORE)
 		printk(KERN_DEBUG "mISDN_register %s %d\n",
 		       dev_name(&dev->dev), dev->id);
+	dev->dev.class = &mISDN_class;
+
 	err = create_stack(dev);
 	if (err)
 		goto error1;
 
-	dev->dev.class = &mISDN_class;
 	dev->dev.platform_data = dev;
 	dev->dev.parent = parent;
 	dev_set_drvdata(&dev->dev, dev);
@@ -249,8 +250,8 @@ mISDN_register_device(struct mISDNdevice *dev,
 
 error3:
 	delete_stack(dev);
-	return err;
 error1:
+	put_device(&dev->dev);
 	return err;
 
 }