static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx)
{
    uint64_t mfindex;

    DPRINTF("xhci_submit(slotid=%d,epid=%d)\n", xfer->slotid, xfer->epid);

    xfer->in_xfer = epctx->type>>2;

    switch(epctx->type) {
    case ET_INTR_OUT:
    case ET_INTR_IN:
        xfer->pkts = 0;
        xfer->iso_xfer = false;
        xfer->timed_xfer = true;
        mfindex = xhci_mfindex_get(xhci);
        xhci_calc_intr_kick(xhci, xfer, epctx, mfindex);
        xhci_check_intr_iso_kick(xhci, xfer, epctx, mfindex);
        if (xfer->running_retry) {
            return -1;
        }
        break;
    case ET_BULK_OUT:
    case ET_BULK_IN:
        xfer->pkts = 0;
        xfer->iso_xfer = false;
        xfer->timed_xfer = false;
        break;
    case ET_ISO_OUT:
    case ET_ISO_IN:
        xfer->pkts = 1;
        xfer->iso_xfer = true;
        xfer->timed_xfer = true;
        mfindex = xhci_mfindex_get(xhci);
        xhci_calc_iso_kick(xhci, xfer, epctx, mfindex);
        xhci_check_intr_iso_kick(xhci, xfer, epctx, mfindex);
        if (xfer->running_retry) {
            return -1;
        }
        break;
    default:
        trace_usb_xhci_unimplemented("endpoint type", epctx->type);
        return -1;
    }

    if (xhci_setup_packet(xfer) < 0) {
        return -1;
    }
    usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);

    xhci_complete_packet(xfer);
    if (!xfer->running_async && !xfer->running_retry) {
        xhci_kick_ep(xhci, xfer->slotid, xfer->epid, xfer->streamid);
    }
    return 0;
}

This vulnerability category highlights issues in resource management where failures to properly release memory, file handles, or other resources can degrade system performance or enable denial-of-service conditions.