Kubuntu 17.10 freezes 50 seconds before KDE Plasma starts

[vmagnin]

I upgraded my Kubuntu 17.04 to 17.10 four days ago.

My PC is booting fast: ~10 seconds to see the greeter. But when I connect to my Plasma session, the greeter is staying ~50 seconds at screen, before Plasma is starting (in ~10 more seconds). There was no problem before upgrading to Kubuntu 17.10.

I connected to a terminal session just after having entered my password in the greeter, and I launched the htop command: all I can say is that there is no cpu eating process. The cpu is nearly idle during these 50 seconds.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: sddm 0.14.0-4ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-12.13-generic 4.13.3
Uname: Linux 4.13.0-12-generic i686
ApportVersion: 2.20.7-0ubuntu2
Architecture: i386
CurrentDesktop: KDE
Date: Fri Oct 6 18:13:42 2017
InstallationDate: Installed on 2012-07-31 (1893 days ago)
InstallationMedia: Kubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
SourcePackage: sddm 0.14.0-4ubuntu1
UpgradeStatus: Upgraded to artful on 2017-10-02 (3 days ago)

[vmagnin (vincent-magnin)]

I made an error: my system is using sddm and not lightdm (although this package is also installed).

[vmagnin (vincent-magnin)]

My system is using sddm, not lightdm (sorry)

[vmagnin (vincent-magnin)]

In JournalErrors.txt I found:

oct. 06 18:01:39 hostname NetworkManager[859]: <warn> [1507305699.2215] dhcp6 (eth2): hostname is not a FQDN, it will be ignored
...
oct. 06 18:02:30 hostname NetworkManager[859]: <warn> [1507305750.0731] dhcp6 (eth2): request timed out

And today with cat /var/log/syslog | grep dhcp6, I found:

Oct 9 17:07:28 pc2 NetworkManager[860]: <info> [1507561648.3667] dhcp-init: Using DHCP client 'dhclient'
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.0766] dhcp4 (eth2): activation: beginning transaction (timeout in 45 seconds)
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.0881] dhcp4 (eth2): dhclient started with pid 1093
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1397] dhcp4 (eth2): address 192.168.1.107
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1398] dhcp4 (eth2): plen 24 (255.255.255.0)
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1398] dhcp4 (eth2): gateway 192.168.1.1
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1398] dhcp4 (eth2): lease time 86400
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1398] dhcp4 (eth2): nameserver '192.168.1.1'
Oct 9 17:07:31 pc2 NetworkManager[860]: <info> [1507561651.1398] dhcp4 (eth2): state changed unknown -> bound
Oct 9 17:07:32 pc2 NetworkManager[860]: <info> [1507561652.4310] dhcp6 (eth2): activation: beginning transaction (timeout in 45 seconds)
Oct 9 17:07:32 pc2 NetworkManager[860]: <warn> [1507561652.4311] dhcp6 (eth2): hostname is not a FQDN, it will be ignored
Oct 9 17:07:32 pc2 NetworkManager[860]: <info> [1507561652.4328] dhcp6 (eth2): dhclient started with pid 1375
Oct 9 17:08:17 pc2 NetworkManager[860]: <warn> [1507561697.4329] dhcp6 (eth2): request timed out

The problem seem to be a problem with NetworkManager, not sddm.

Perhaps it is related to this bug:
"Bug 1334050 - Cannot prevent NetworkManager from using DHCPv6"
https://bugzilla.redhat.com/show_bug.cgi?id=1334050

[vmagnin (vincent-magnin)]

The problem seem to be a "timed out" problem with NetworkManager 1.8.4-1ubuntu1, not sddm.

[vmagnin (vincent-magnin)]

I finally reinstalled my system using the Kubuntu 17.10 64 bits ISO today.
It solved the problem.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.