[regression] Can't log in to Wayland Gnome sessions at all

[Daniel van Vugt]

Today I can't log in to Gnome Wayland sessions at all. Although the usual Xorg Gnome sessions work.

When a Wayland login fails I get dumped to a black VT screen and digging around via SSH, journalctl shows:

Jul 13 12:56:55 haz failsafeXServer[2100]: xinit: giving up
Jul 13 12:56:55 haz failsafeXServer[2100]: xinit: unable to connect to X server: Connection refused
Jul 13 12:56:55 haz failsafeXServer[2100]: xinit: server error

which is weird. I'm not trying to use X.

[Daniel van Vugt (vanvugt)]

Bisected: The problem started in gdm 3.24.2-1ubuntu6

FAILS: 3.24.2-1ubuntu7
FAILS: 3.24.2-1ubuntu6
WORKS: 3.24.2-1ubuntu5

So the workaround is to downgrade to:
https://launchpad.net/ubuntu/+source/gdm3/3.24.2-1ubuntu5/+build/13073822

[Daniel van Vugt (vanvugt)]

journalctl shows (grepping just gdm):

Jul 13 14:30:44 haz gdm-launch-environment][1051]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
Jul 13 14:30:44 haz systemd[1]: Created slice User Slice of gdm.
Jul 13 14:30:44 haz systemd-logind[905]: New session c1 of user gdm.
Jul 13 14:30:44 haz systemd[1]: Started Session c1 of user gdm.
Jul 13 14:30:44 haz systemd[1061]: pam_unix(systemd-user:session): session opened for user gdm by (uid=0)
Jul 13 14:30:46 haz gnome-shell[1089]: JS WARNING: [resource:///org/gnome/shell/gdm/util.js 331]: reference to undefined property this._preemptingService
Jul 13 14:31:15 haz gdm-password][1429]: pam_unix(gdm-password:session): session opened for user dan by (uid=0)
Jul 13 14:31:15 haz gdm3[1046]: Cannot find a command for specified session: ubuntu-wayland
Jul 13 14:31:15 haz systemd[1]: gdm.service: Main process exited, code=exited, status=1/FAILURE
Jul 13 14:31:15 haz systemd[1]: gdm.service: Unit entered failed state.
Jul 13 14:31:15 haz systemd[1]: gdm.service: Triggering OnFailure= dependencies.
Jul 13 14:31:15 haz systemd[1]: gdm.service: Failed with result 'exit-code'.
Jul 13 14:31:16 haz systemd[1]: gdm.service: Service hold-off time over, scheduling restart.
Jul 13 14:31:16 haz gdm-launch-environment][1517]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
Jul 13 14:31:16 haz systemd-logind[905]: New session c2 of user gdm.
Jul 13 14:31:16 haz systemd[1]: Started Session c2 of user gdm.

[Daniel van Vugt (vanvugt)]

Debug log

[Launchpad Janitor (janitor)]

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

[Didier Roche (didrocks)]

For people interested into glory details:
https://irclogs.ubuntu.com/2017/07/13/%23ubuntu-desktop.html#t06:19
(to 07:22)

[Launchpad Janitor (janitor)]

This bug was fixed in the package gdm3 - 3.24.2-1ubuntu8

---------------
gdm3 (3.24.2-1ubuntu8) artful; urgency=medium

  * Avoid double-NULL terminated array that breaks append operations
    and so prevents Wayland sessions from working (LP: #1704050)

 -- Daniel van Vugt <email address hidden> Thu, 13 Jul 2017 16:29:46 +0800

[Owen Pimm (owen-pimm)]

Hi Daniel. I've just carried out a fresh install of Ubuntu 17.10. This problem is affecting me. I can log in using X but not Wayland. As I can log into X, this hasn't stopped me but thought I'd let you know, I'm also affected. Since it looks as though you've provided the fix, I assume this will be corrected as I continue to do software updates as usual. If not, please advise. Appreciate your generous help.
Regards Owen