static int ehci_fill_queue(EHCIPacket *p)
{
    USBEndpoint *ep = p->packet.ep;
    EHCIQueue *q = p->queue;
    EHCIqtd qtd = p->qtd;
    uint32_t qtdaddr;

    for (;;) {
        if (NLPTR_TBIT(qtd.next) != 0) {
            break;
        }
        qtdaddr = qtd.next;
        /*
         * Detect circular td lists, Windows creates these, counting on the
         * active bit going low after execution to make the queue stop.
         */
        QTAILQ_FOREACH(p, &q->packets, next) {
            if (p->qtdaddr == qtdaddr) {
                goto leave;
            }
        }
        if (get_dwords(q->ehci, NLPTR_GET(qtdaddr),
                       (uint32_t *) &qtd, sizeof(EHCIqtd) >> 2) < 0) {
            return -1;
        }
        ehci_trace_qtd(q, NLPTR_GET(qtdaddr), &qtd);
        if (!(qtd.token & QTD_TOKEN_ACTIVE)) {
            break;
        }
        if (!ehci_verify_pid(q, &qtd)) {
            ehci_trace_guest_bug(q->ehci, "guest queued token with wrong pid");
            break;
        }
        p = ehci_alloc_packet(q);
        p->qtdaddr = qtdaddr;
        p->qtd = qtd;
        if (ehci_execute(p, "queue") == -1) {
            return -1;
        }
        assert(p->packet.status == USB_RET_ASYNC);
        p->async = EHCI_ASYNC_INFLIGHT;
    }
leave:
    usb_device_flush_ep_queue(ep->dev, ep);
    return 1;
}

The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.