[Bug 1850704] Autopkgtest regression report (systemd/237-3ubuntu10.33)

[Ubuntu SRU Bot]

All autopkgtests for the newly accepted systemd (237-3ubuntu10.33) for bionic have finished running.
The following regressions have been reported in tests triggered by the package:

gvfs/1.36.1-0ubuntu1.3.3 (ppc64el, amd64)
dovecot/1:2.2.33.2-1ubuntu4.5 (armhf)
umockdev/0.11.1-1 (ppc64el)


Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-
migration/bionic/update_excuses.html#systemd

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

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https://bugs.launchpad.net/bugs/1850704

Title:
  networkd doesn't set MTUBytes if interface is already up

Status in systemd:
  Fix Released
Status in systemd package in Ubuntu:
  Fix Released
Status in systemd source package in Bionic:
  Fix Committed

Bug description:
  [impact]

  if a networkd .network file specifies a [Link] section with
  MTUBytes=XXX set, networkd will only apply that mtu if the interface
  is down when networkd starts; if the interface is already up, the mtu
  won't be applied.

  [test case]

  on a bionic system, create a .network file like:

  [Match]
  Name=ens8

  [Link]
  MTUBytes=6666

  then, reboot.  The interface should be set correctly with that mtu:

  $ ip l show ens8
  3: ens8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 6666 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
      link/ether 52:54:00:30:4c:1e brd ff:ff:ff:ff:ff:ff

  
  now, manually change the interface back to 1500 mtu, and restart networkd, then recheck the mtu:

  $ ip l show ens8
  3: ens8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 6666 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
      link/ether 52:54:00:30:4c:1e brd ff:ff:ff:ff:ff:ff
  $ sudo ip l set mtu 1500 dev ens8
  $ ip l show ens8
  3: ens8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
      link/ether 52:54:00:30:4c:1e brd ff:ff:ff:ff:ff:ff
  $ sudo systemctl restart systemd-networkd
  $ ip l show ens8
  3: ens8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
      link/ether 52:54:00:30:4c:1e brd ff:ff:ff:ff:ff:ff

  [regression potential]

  low, but any regression would likely involve failure to correctly set
  the configured mtu.

  this is needed only in bionic, it's fixed in disco and later already.

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