static int virtio_net_has_buffers(VirtIONetQueue *q, int bufsize)
{
    VirtIONet *n = q->n;
    if (virtio_queue_empty(q->rx_vq) ||
        (n->mergeable_rx_bufs &&
         !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) {
        virtio_queue_set_notification(q->rx_vq, 1);

        /* To avoid a race condition where the guest has made some buffers
         * available after the above check but before notification was
         * enabled, check for available buffers again.
         */
        if (virtio_queue_empty(q->rx_vq) ||
            (n->mergeable_rx_bufs &&
             !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) {
            return 0;
        }
    }

    virtio_queue_set_notification(q->rx_vq, 0);
    return 1;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.