PCI: Fix refcount issue in pci_create_root_bus() error recovery path

After calling device_register(&bridge->dev), the bridge is reference-
counted, and it is illegal to call kfree() on it except in the release
function.

[bhelgaas: changelog, use put_device() after device_register() failure]
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org

drivers/pci/probe.c

@@ -1711,12 +1711,16 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	bridge->dev.release = pci_release_bus_bridge_dev;
 	dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
 	error = pcibios_root_bridge_prepare(bridge);
-	if (error)
-		goto bridge_dev_reg_err;
+	if (error) {
+		kfree(bridge);
+		goto err_out;
+	}
 
 	error = device_register(&bridge->dev);
-	if (error)
-		goto bridge_dev_reg_err;
+	if (error) {
+		put_device(&bridge->dev);
+		goto err_out;
+	}
 	b->bridge = get_device(&bridge->dev);
 	device_enable_async_suspend(b->bridge);
 	pci_set_bus_of_node(b);
@@ -1772,8 +1776,6 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 class_dev_reg_err:
 	put_device(&bridge->dev);
 	device_unregister(&bridge->dev);
-bridge_dev_reg_err:
-	kfree(bridge);
 err_out:
 	kfree(b);
 	return NULL;