static int usb_enumerate_device_otg(struct usb_device *udev)
{
	int err = 0;

#ifdef	CONFIG_USB_OTG
	/*
	 * OTG-aware devices on OTG-capable root hubs may be able to use SRP,
	 * to wake us after we've powered off VBUS; and HNP, switching roles
	 * "host" to "peripheral".  The OTG descriptor helps figure this out.
	 */
	if (!udev->bus->is_b_host
			&& udev->config
			&& udev->parent == udev->bus->root_hub) {
		struct usb_otg_descriptor	*desc = NULL;
		struct usb_bus			*bus = udev->bus;
		unsigned			port1 = udev->portnum;

		/* descriptor may appear anywhere in config */
		err = __usb_get_extra_descriptor(udev->rawdescriptors[0],
				le16_to_cpu(udev->config[0].desc.wTotalLength),
				USB_DT_OTG, (void **) &desc, sizeof(*desc));
		if (err || !(desc->bmAttributes & USB_OTG_HNP))
			return 0;

		dev_info(&udev->dev, "Dual-Role OTG device on %sHNP port\n",
					(port1 == bus->otg_port) ? "" : "non-");

		/* enable HNP before suspend, it's simpler */
		if (port1 == bus->otg_port) {
			bus->b_hnp_enable = 1;
			err = usb_control_msg(udev,
				usb_sndctrlpipe(udev, 0),
				USB_REQ_SET_FEATURE, 0,
				USB_DEVICE_B_HNP_ENABLE,
				0, NULL, 0,
				USB_CTRL_SET_TIMEOUT);
			if (err < 0) {
				/*
				 * OTG MESSAGE: report errors here,
				 * customize to match your product.
				 */
				dev_err(&udev->dev, "can't set HNP mode: %d\n",
									err);
				bus->b_hnp_enable = 0;
			}
		} else if (desc->bLength == sizeof
				(struct usb_otg_descriptor)) {
			/* Set a_alt_hnp_support for legacy otg device */
			err = usb_control_msg(udev,
				usb_sndctrlpipe(udev, 0),
				USB_REQ_SET_FEATURE, 0,
				USB_DEVICE_A_ALT_HNP_SUPPORT,
				0, NULL, 0,
				USB_CTRL_SET_TIMEOUT);
			if (err < 0)
				dev_err(&udev->dev,
					"set a_alt_hnp_support failed: %d\n",
					err);
		}
	}
#endif
	return err;
}
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.