Hi,

I just registered with LinuxQuestions.org. I am an experienced Unix user, with over twenty years as a professional.

My question is as follows. I am running Ubuntu 18.04 with the latest patches on VirtualBox 6.0.8. Ubuntu has been running without any issues for months. Today, however, I saw that the Ubuntu Livepatch had been applied. I checked to see if there were additional patches,
and there was a small patch (600+kb), it was installed.

As requested, the system was rebooted and when it came back up the usual Ubuntu login GUI screen was nowhere to be found, just a blank (i.e., purple/mauve) screen with "ubuntu*" printed at the bottom of the screen.

Other than the missing login screen, the system appears to be running properly. I say that because I'm using Ubuntu to run a web page and I'm able to access the web page from outside my LAN.

I used ssh to log in, and everything seems to be up to date:

--------------------------------------------------------------------------
Welcome to Ubuntu 18.04.2 LTS (GNU/Linux 4.15.0-52-generic x86_64)

* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage

* Ubuntu's Kubernetes 1.14 distributions can bypass Docker and use containerd
directly, see https://bit.ly/ubuntu-containerd or try it now with

snap install microk8s --classic

* Canonical Livepatch is enabled.
- All available patches applied.

0 packages can be updated.
0 updates are security updates.

Last login: Sun Apr 21 15:06:59 2019 from 192.168.0.180
--------------------------------------------------------------------------

This looks like a bug. (FYI, I do have TimeShift installed, which I may need to use.) Anyone else experienced this issue or have further suggestions?

Thanks.

If you haven't done this yet, first read about the patch that was applied (what it does and what it might affect). If nothing in the patch description gives you any clues, review your startup logs to find out what's happening during startup or, if you haven't, exit out of the purple screen during boot to follow the startup processes and identify any error messages.

My guess is that the patch in question may have messed up your GDM or Xorg configuration. To find out if your GDM is the issue, try to run it from a terminal after the machine boots up. if it doesn't start, any additional error messages may help clue you in on what's wrong. Since your machine is otherwise working fine, and if GDM turns out to be broken, try reinstalling GDM and reboot. If you still don't get the log-in screen, try to initiate a new Xorg configuration and reboot.

@sntniz Thanks for your reply.

I rolled back using a previous Timeshift snapshot and after rebooting everything came up normally. The system ran for a couple of days without apparent incident. Yesterday I decided to try to do a software update (approx. 90 packages were available) so I took another Timeshift snapshot. As expected, after the software update and subsequent reboot, the issue was identical and again the login session didn't come up.

From /var/log/syslog, here is where it appears the issue is:

Jun 29 22:16:16 hawkmcduck dbus-daemon[12834]: [session uid=1000 pid=12834] AppArmor D-Bus mediation is enabled
Jun 29 22:16:16 hawkmcduck gnome-session[1397]: gnome-session-binary[1397]: WARNING: Lost name on bus: org.gnome.SessionManager
Jun 29 22:16:16 hawkmcduck gnome-session-binary[1397]: WARNING: Lost name on bus: org.gnome.SessionManager
Jun 29 22:16:16 hawkmcduck gnome-session[1397]: gnome-session-binary[1397]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Jun 29 22:16:16 hawkmcduck gnome-session-binary[1397]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Jun 29 22:16:16 hawkmcduck gnome-software[1975]: lost session service
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping Thunderbolt system service...
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping PackageKit Daemon...
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopped target Sound Card.
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping Save/Restore Sound Card State...
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopped target Graphical Interface.
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopped target Multi-User System.
Jun 29 22:16:16 hawkmcduck gnome-shell[2148]: gnome-shell: Fatal IO error 0 (Success) on X server :0.
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping The Apache HTTP Server...
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (**) Option "fd" "24"
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping Dispatcher daemon for systemd-networkd...
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (II) event0 - Power Button: device removed
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (**) Option "fd" "27"
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (II) event1 - Sleep Button: device removed
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (**) Option "fd" "28"
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (II) event5 - Video Bus: device removed
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (**) Option "fd" "29"
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (II) event6 - VirtualBox mouse integration: device removed
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (**) Option "fd" "30"
Jun 29 22:16:16 hawkmcduck /usr/lib/gdm3/gdm-x-session[1386]: (II) event4 - VirtualBox USB Tablet: device removed
Jun 29 22:16:16 hawkmcduck systemd[1]: Stopping LSB: automatic crash report generation...

I tried re-installing the desktop with:

sudo apt-get install --reinstall ubuntu-desktop

but after a reboot the issue persisted.

I then tried re-installing the gnome shell using

sudo apt-get install gnome-shell ubuntu-gnome-desktop

but again, after a reboot, the issue was still there.

To further this issue, I decided to determine, by trial and error and using timeshift, which of the 90 or so packages in the software update was preventing the login screen to come up. Initially the following updates were presented:

The following packages will be upgraded:
apt apt-utils cups cups-bsd cups-client cups-common cups-core-drivers cups-daemon cups-ipp-utils cups-ppdc cups-server-common gedit gedit-common gir1.2-geocodeglib-1.0 gir1.2-gst-plugins-base-1.0
gir1.2-gstreamer-1.0 gir1.2-mutter-2 gnome-shell gnome-shell-common gstreamer1.0-alsa gstreamer1.0-gl gstreamer1.0-gtk3 gstreamer1.0-libav gstreamer1.0-plugins-base gstreamer1.0-plugins-base-apps
gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly gstreamer1.0-pulseaudio gstreamer1.0-tools gstreamer1.0-vaapi gstreamer1.0-x gvfs gvfs-backends gvfs-bin gvfs-common gvfs-daemons gvfs-fuse
gvfs-libs libapt-inst2.0 libapt-pkg5.0 libcups2 libcupscgi1 libcupsimage2 libcupsmime1 libcupsppdc1 libegl1 libgeocode-glib0 libgl1 libgles2 libglvnd0 libglx0 libgstreamer-gl1.0-0
libgstreamer-plugins-bad1.0-0 libgstreamer-plugins-base1.0-0 libgstreamer-plugins-good1.0-0 libgstreamer1.0-0 libio-socket-ssl-perl libmutter-2-0 libnet-ssleay-perl libnss-myhostname
libnss-systemd libpam-systemd libpython2.7 libpython2.7-minimal libpython2.7-stdlib libpython3.6 libpython3.6-minimal libpython3.6-stdlib libssl1.1 libsystemd0 libudev1 libwww-perl mutter mutter-common
openssl python3-cryptography python3-gdbm python3.6 python3.6-minimal snapd systemd systemd-sysv udev update-notifier update-notifier-common xserver-common xserver-xephyr xserver-xorg-core
xserver-xorg-legacy xwayland

After more than a few reboots, the following four packages appear to be problematic:

$ sudo apt list --upgradable
Listing... Done
gir1.2-mutter-2/bionic-updates 3.28.4-0ubuntu18.04.1 amd64 [upgradable from: 3.28.3+git20190124-0ubuntu18.04.2]
gnome-shell/bionic-updates 3.28.4-0ubuntu18.04.1 amd64 [upgradable from: 3.28.3+git20190124-0ubuntu18.04.2]
gnome-shell-common/bionic-updates,bionic-updates 3.28.4-0ubuntu18.04.1 all [upgradable from: 3.28.3+git20190124-0ubuntu18.04.2]
libmutter-2-0/bionic-updates 3.28.4-0ubuntu18.04.1 amd64 [upgradable from: 3.28.3+git20190124-0ubuntu18.04.2]
$ sudo apt install gnome-shell
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
gir1.2-mutter-2 gnome-shell-common libmutter-2-0
Suggested packages:
gir1.2-telepathyglib-0.12 gir1.2-telepathylogger-0.2 chrome-gnome-shell gnome-themes-standard-data switcheroo-control
The following packages will be upgraded:
gir1.2-mutter-2 gnome-shell gnome-shell-common libmutter-2-0
4 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 2,200 kB of archives.
After this operation, 14.3 kB of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.
$

My conclusion that the libmutter-2-0 package prevents the login screen from coming up. The gnome-shell, gnome-shell-common, and gir1.2-mutter-2 packages rely on libmutter-2-0 package, as can be seen above.

Other than this, when the four packages above are not upgraded, my Ubuntu 18.04 LTS system appears to function properly.

I'm not sure how to progress this issue further, whether I should report this to the Ubuntu or debian development team (or to whom). Anybody have further suggestions, let me know please.

Nice work. I expect you're paying for Livepatch, so raise a bug against Canonical.

Livepatch is installed (tho' I disabled it yesterday out of a sense of paranoia) but I didn't know it wasn't free, and in any case I'm not paying for it.

How can I raise a bug against Canonical?

The original issue remains.

Before updating the software on my system, I take a Timeshift snapshot. Before updating, I check for any updates to mutter-2 (i.e., Mutter or the Mutter Window Manager) in Software Updater, and de-select them. I then update the software and reboot. After the reboot, if the login screen comes up, well and good and I take a second snapshot with Timeshift before updating a second time with the updates to Mutter.

Consistently and so far without exception, the Mutter updates cause the GUI login to NOT come up, and I have to restore again from the latest snapshot.

I would sure like to report this issue to whichever developers are responsible for Mutter. According to information in Software Updater regarding Mutter and the Mutter Window Manager, that appears to be Daniel van Vugt and/or Iain Lane.