static USBPort *xhci_lookup_uport(XHCIState *xhci, uint32_t *slot_ctx)
{
    USBPort *uport;
    char path[32];
    int i, pos, port;

    port = (slot_ctx[1]>>16) & 0xFF;
    if (port < 1 || port > xhci->numports) {
        return NULL;
    }
    port = xhci->ports[port-1].uport->index+1;
    pos = snprintf(path, sizeof(path), "%d", port);
    for (i = 0; i < 5; i++) {
        port = (slot_ctx[0] >> 4*i) & 0x0f;
        if (!port) {
            break;
        }
        pos += snprintf(path + pos, sizeof(path) - pos, ".%d", port);
    }

    QTAILQ_FOREACH(uport, &xhci->bus.used, next) {
        if (strcmp(uport->path, path) == 0) {
            return uport;
        }
    }
    return NULL;
}

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.