gdm3 not starting on ubuntu 20.04

Question

I recently upgraded from Ubuntu 18.04 to 20.04 as I was having this issue as well (with a different error). I was hoping upgrading would fix it. After upgrading Ubuntu worked a few times but now it won't start. I've been trying for ages to fix this including un-commenting #WaylandEnable=false, however when I tried that the laptop wouldn't start at all and stayed on the line dev/sda1: clean, xxxxxx/xxxxx files, xxxxxxx/xxxxxxx blocks and wouldn't go any further.

It might help to know this is a very old laptop >10years dell xps. Ubuntu works fine when it starts and is the only OS installed.

The output of systemctl status gdm is (I am typing this so might be errors):

Started GNOME Display Manager.
gdm-launch-environment [963]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
gdm3[958]: Gdm Display: Session never registered, failing
gdm3[958]: Child process -1011 was already dead.
gdm3[958]: Child process -1011 was already dead.
gdm-launch-environment [1324]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
gdm3[958]: Child process -1346 was already dead.

I would really like to get this fixed as it is a laptop I use a lot. I also really quickly tried to install lightdm but ubuntu told me there isn't enough disk space in /var/cache/apt/archives (which I am pretty sure is untrue last I checked I had about 9GB free) but I can delete some stuff and install lightdm if that is the best fix.

Rather than upgrading, try reinstalling fresh: that way the new system will be optimally configured, not using settings anymore that are carried over by previous installations. If such problem then still persists, then you still can start debugging. — vanadium, Jul 04 '20 at 11:13

score 2 · Answer 1 · answered Jul 14 '20 at 12:16

2

I created the file /usr/share/gnome-session/sessions/gdm-shell.session containing:

[GNOME Session]
Name=Computer

and then I could use GDM3 as the session login manager again for the first time in years.

answered Jul 14 '20 at 12:16

Run.dll

21

score 0 · Answer 2 · answered Nov 04 '20 at 08:13

0

I have the same issue - I did notice that the system was asking me to update the gdm.conf file on upgrade, which [of course] I ignored...

Now the symptoms are the same as above, however, if I run a

sudo startx

the session manager starts. It is a work around and a fix is still in search. I am pretty sure this is a config issue, as I had that in 18.04 upgrade from 16.04 - then a configuration option needed to change.

answered Nov 04 '20 at 08:13

Bate Vladi

1

Thanks haven't tried this as I reinstalled Ubuntu. Good to have a workaround at least – danbeggan Nov 16 '20 at 11:01

score 0 · Answer 3 · answered Oct 18 '21 at 17:55

Same problem as danbeggan, as above.
Also running a legacy laptop, also successfully upgraded recently from Ubuntu 18.04 to Ubuntu 20.04, also with Ubuntu the only o/s installed, also Gnome desktop environment worked for about a month (with some screen freezes), until finally Gnome fails to provide login screen. That is, my laptop (after sucess with the splash screen displaying the Ubuntu logo and the spinning icon) only provides a blank screen, with a flashing cursor in top-left corner. AFAIK it tries to get to the log screen a few times, and then gives up. It's still possible fortunately login from terminal. Same error output as above: "Gdm Display: Session never registered, failing"

Also checked the logfile for X server. That is, from terminal, run: 'sudo nano /home/[userID]/.local/share/xorg/Xorg.0.log' There's a message included therein at the bottom of the file: "Server terminated with error" The "fatal server error" started after applying a recent update (including a firmware update).

My workaround: Abandon GNOME, switch to a different desktop environment, such as XFCE. Using simple instructions found online, installed XFCE. Run from terminal: 'sudo apt update' 'sudo apt install xfce4' When prompted with a pop-up message, make "lightdm" (the lighter, less resource-intensive display manager, that is, Xfce) the DEFAULT for your X server. This means, afaik, ALSO switching to Thunar as your file system manager.Then, from the terminal: 'sudo reboot' After a short wait, you get to the unfamiliar Xfce login screen, then after login, and another short wait, you get back your usable computer.

score 0 · Answer 4 · answered Feb 10 '22 at 16:34

I had the same behavior several times ago. So I've just realized I found it could happened when file system /home is mounted from disk that label changed when another Windows partition was installed and renaming id's, I made chages in my Windows partitions just before this problem happened. In my case sdb7 was changed to sdb8 then /home pointed to sdb7, I changed to sdb8 editing fstab, and reboot, then it worked fine and gdm started as usual. Here is detailed steps. gdm cannot start session, but Linux worked, so I can connect it via ssh.

        root@asampau-System-Product-Name:~# /etc/init.d/gdm3 status
    ● gdm.service - GNOME Display Manager
     Loaded: loaded (/lib/systemd/system/gdm.service; static; vendor preset: enabled)
     Active: active (running) since Thu 2022-02-10 08:56:11 -03; 9min ago
    Process: 1208 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
    Process: 1239 ExecStartPre=/usr/lib/gdm3/gdm-wait-for-drm (code=exited, status=0/SUCCESS)
   Main PID: 1244 (gdm3)
      Tasks: 3 (limit: 19034)
     Memory: 37.6M
     CGroup: /system.slice/gdm.service
             └─1244 /usr/sbin/gdm3
    feb 10 08:56:15 asampau-System-Product-Name /usr/lib/gdm3/gdm-x-session[1345]: (II) UnloadModule: "libinput"

I saw both filesystems / and /home were in sda5, but /home shoud be in a different disk.

root@asampau-System-Product-Name:~# df -h /
S.ficheros     Tamaño Usados  Disp Uso% Montado en
/dev/sda5         83G    21G   58G  26% /

I saw it was empty!

root@asampau-System-Product-Name:~# ls -l /home/asampau/
total 32
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Descargas
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Documentos
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Escritorio
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Imágenes
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Música
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Plantillas
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Público
drwxr-xr-x 2 asampau asampau 4096 may 28  2020 Vídeos
root@asampau-System-Product-Name:~# ls -l /home/asampau/Descargas/
total 0
root@asampau-System-Product-Name:~# ls -l /home/asampau/
.bash_history              .config/                   Escritorio/                Música/                    Público/
.bash_logout               .dbus/                     .gnupg/                    .nv/                       .ssh/
.bashrc                    Descargas/                 Imágenes/                  Plantillas/                .sudo_as_admin_successful
.cache/                    Documentos/                .local/                    .profile                   Vídeos/
root@asampau-System-Product-Name:~# ls -l /home/asampau/Música/
total 0

Suspect /home was mounted at the same FS as / (see line /home at sdb7)

root@asampau-System-Product-Name:~# df -h /home
S.ficheros     Tamaño Usados  Disp Uso% Montado en
/dev/sda5         83G    21G   58G  26% /
root@asampau-System-Product-Name:~# cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda5 during installation
UUID=66574cd6-b13c-479d-84c5-be77f40ac4da /               ext4    errors=remount-ro 0       1
/dev/sdb7       /home/               ext4    errors=remount-ro 0       0
# /boot/efi was on /dev/sda2 during installation
UUID=5C52-E857  /boot/efi       vfat    umask=0077      0       1
/swapfile       none            swap    sw              0       0
/dev/sdc6       none            swap    sw              0       0
/dev/sdc5       /mnt/sdc5              ext3    errors=remount-ro 0       0
/dev/sdc7       /mnt/sdc7               ext3    errors=remount-ro 0       0
/dev/sdc8       /mnt/sdc8               ext3    errors=remount-ro 0       0
/dev/sdc9       /mnt/sdc9               ext3    errors=remount-ro 0       0
/dev/sdc11      /mnt/sdc11               ext3    errors=remount-ro 0       0

Believe there was an error when my Linuz tried to mount /home at sdb7, I fixed fstab by changed sdb7 to sdb8 (see sfdisk sdb8 is the Linux Partition so sdb7 is EFI)

root@asampau-System-Product-Name:~# vi /etc/fstab
root@asampau-System-Product-Name:~# sfdisk -l /dev/sdb
Disco /dev/sdb: 1,84 TiB, 2000398934016 bytes, 3907029168 sectores
Disk model: WDC WD20PURZ-85G
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 4096 bytes
Tamaño de E/S (mínimo/óptimo): 4096 bytes / 4096 bytes
Tipo de etiqueta de disco: gpt
Identificador del disco: C90DD2B8-9E7B-4A97-9A4A-C104A45C0D01
Dispositivo   Comienzo      Final   Sectores Tamaño Tipo
/dev/sdb1           34      32767      32734    16M Reservado para Microsoft
/dev/sdb2        32768 2048032767 2048000000 976,6G Datos básicos de Microsoft
/dev/sdb3   2048032768 2560032767  512000000 244,1G Datos básicos de Microsoft
/dev/sdb4   2560032768 2867232767  307200000 146,5G Datos básicos de Microsoft
/dev/sdb5   2867232768 3072030719  204797952  97,7G Datos básicos de Microsoft
/dev/sdb6   3072032768 3584030719  511997952 244,1G Datos básicos de Microsoft
/dev/sdb7   3584032768 3585083391    1050624   513M Sistema EFI
/dev/sdb8   3585083392 3907028991  321945600 153,5G Sistema de ficheros de Linux
root@asampau-System-Product-Name:~# cat /etc/fstab
/etc/fstab: static file system information.

Use 'blkid' to print the universally unique identifier for a
device; this may be used with UUID= as a more robust way to name devices
that works even if disks are added and removed. See fstab(5).

<file system> <mount point>   <type>  <options>       <dump>  <pass>
/ was on /dev/sda5 during installation
UUID=66574cd6-b13c-479d-84c5-be77f40ac4da /               ext4    errors=remount-ro 0       1
/dev/sdb8       /home/               ext4    errors=remount-ro 0       0
/boot/efi was on /dev/sda2 during installation
UUID=5C52-E857  /boot/efi       vfat    umask=0077      0       1
/swapfile       none            swap    sw              0       0
/dev/sdc6       none            swap    sw              0       0
/dev/sdc5       /mnt/sdc5              ext3    errors=remount-ro 0       0
/dev/sdc7       /mnt/sdc7               ext3    errors=remount-ro 0       0
/dev/sdc8       /mnt/sdc8               ext3    errors=remount-ro 0       0
/dev/sdc9       /mnt/sdc9               ext3    errors=remount-ro 0       0
/dev/sdc11      /mnt/sdc11               ext3    errors=remount-ro 0       0
root@asampau-System-Product-Name:~#

It's done.

It could be happen after upgrade or install process. May it help. Regards — Andrés Esteban Sampaulo, Feb 16 '22 at 21:01

gdm3 not starting on ubuntu 20.04

4 Answers4

/etc/fstab: static file system information.

Use 'blkid' to print the universally unique identifier for a

device; this may be used with UUID= as a more robust way to name devices

that works even if disks are added and removed. See fstab(5).

<file system> <mount point> <type> <options> <dump> <pass>

/ was on /dev/sda5 during installation

/boot/efi was on /dev/sda2 during installation

Linked