Hi, I just had the what seems to be the same bug happen to me.
This is the relevant output form pstree: ,---- | `-sudo,21446 apt dist-upgrade | `-apt,21447 dist-upgrade | `-dpkg,22875 --status-fd 39 --configure --pending | `-ifupdown.postin,22876 /var/lib/dpkg/info/ifupdown.postinst configure 0.8.33 | `-systemctl,24561 restart ifupdown-pre.service ifupdown-wait-online.service | `-systemd-tty-ask,24568 --watch `---- Killing the systemd-tty-ask-password-agent process leads to the following output... ,---- | Setting up ifupdown (0.8.34) ... | Job for ifupdown-wait-online.service failed because the control process exited with error code. | See "systemctl status ifupdown-wait-online.service" and "journalctl -xe" for details. `---- Package configuration does not fail, however, the eth0 interface which provides main connectivity stays unconfigured. This is the ifupdown configuration for said eth0 interface: ,---- | # The primary network interface | allow-hotplug eth0 | iface eth0 inet dhcp | # This is an autoconfigured IPv6 interface | iface eth0 inet6 auto `---- Cheers, -Hilko
