[PATCH v2] usb: fix reference leak in usb_new_device()

[Ma Ke]

When device_add(&udev->dev) failed, calling put_device() to explicitly
release udev->dev. And the routine which calls usb_new_device() does
not call put_device() when an error occurs. As comment of device_add()
says, 'if device_add() succeeds, you should call device_del() when you
want to get rid of it. If device_add() has not succeeded, use only
put_device() to drop the reference count'.

Found by code review.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 9f8b17e643fe ("USB: make usbdevices export their device nodes instead of using a separate class")
Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
---
Changes in v2:
- modified the bug description to make it more clear;
- added the missed part of the patch.
---
 drivers/usb/core/hub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 4b93c0bd1d4b..ddd572312296 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2651,6 +2651,7 @@ int usb_new_device(struct usb_device *udev)
 	err = device_add(&udev->dev);
 	if (err) {
 		dev_err(&udev->dev, "can't device_add, error %d\n", err);
+		put_device(&udev->dev);
 		goto fail;
 	}
 
@@ -2663,13 +2664,13 @@ int usb_new_device(struct usb_device *udev)
 		err = sysfs_create_link(&udev->dev.kobj,
 				&port_dev->dev.kobj, "port");
 		if (err)
-			goto fail;
+			goto out_del_dev;
 
 		err = sysfs_create_link(&port_dev->dev.kobj,
 				&udev->dev.kobj, "device");
 		if (err) {
 			sysfs_remove_link(&udev->dev.kobj, "port");
-			goto fail;
+			goto out_del_dev;
 		}
 
 		if (!test_and_set_bit(port1, hub->child_usage_bits))
@@ -2683,6 +2684,9 @@ int usb_new_device(struct usb_device *udev)
 	pm_runtime_put_sync_autosuspend(&udev->dev);
 	return err;
 
+out_del_dev:
+	device_del(&udev->dev);
+	put_device(&udev->dev);
 fail:
 	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
 	pm_runtime_disable(&udev->dev);
-- 
2.25.1