static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep)
{
	struct dwc3_gadget_ep_cmd_params params;
	struct dwc3_request		*req;
	int				starting;
	int				ret;
	u32				cmd;

	if (!dwc3_calc_trbs_left(dep))
		return 0;

	starting = !(dep->flags & DWC3_EP_BUSY);

	dwc3_prepare_trbs(dep);
	req = next_request(&dep->started_list);
	if (!req) {
		dep->flags |= DWC3_EP_PENDING_REQUEST;
		return 0;
	}

	memset(&params, 0, sizeof(params));

	if (starting) {
		params.param0 = upper_32_bits(req->trb_dma);
		params.param1 = lower_32_bits(req->trb_dma);
		cmd = DWC3_DEPCMD_STARTTRANSFER;

		if (usb_endpoint_xfer_isoc(dep->endpoint.desc))
			cmd |= DWC3_DEPCMD_PARAM(dep->frame_number);
	} else {
		cmd = DWC3_DEPCMD_UPDATETRANSFER |
			DWC3_DEPCMD_PARAM(dep->resource_index);
	}

	ret = dwc3_send_gadget_ep_cmd(dep, cmd, &params);
	if (ret < 0) {
		/*
		 * FIXME we need to iterate over the list of requests
		 * here and stop, unmap, free and del each of the linked
		 * requests instead of what we do now.
		 */
		if (req->trb)
			memset(req->trb, 0, sizeof(struct dwc3_trb));
		dep->queued_requests--;
		dwc3_gadget_del_and_unmap_request(dep, req, ret);
		return ret;
	}

	dep->flags |= DWC3_EP_BUSY;

	if (starting) {
		dep->resource_index = dwc3_gadget_ep_get_transfer_index(dep);
		WARN_ON_ONCE(!dep->resource_index);
	}

	return 0;
}
The software does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.