That sounds like it is related. While doing more debug I found that network-manager starts dhclient in forground mode (-d) and that is not affected by bug 1551351. But regardless of how it was started, dhclient seem not to react on SIGHUP. Maybe disconnecting from the network manually uses a more aggressive method of stopping the dhclient than just doing a shutdown or reboot. The system probably goes into the mode of first trying to send SIGHUP to running processes, then wait a bit and finally doing a SIGTERM. That would explain the increased time.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1551415 Title: systemctl stop networking hang / timeout To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1551415/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs