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@vger.kernel.org Fixes: 9f8b17e643fe ("USB: make usbdevices export their device nodes instead of using a separate class") Signed-off-by: Ma Ke make_ruc2021@163.com --- 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);