Bug#926309: gdm3: gdm-x-session calls Xsession with broken arguments

[Matijs van Zuijlen]

Package: gdm3
Version: 3.32.0-1
Severity: normal

Dear maintainer,

Since a couple of weeks, I guess, logging into the GNOME X session from
gdm3 shows a popup with the message:

    Xsession: unsupported number of arguments (5); falling back to default session.

This message also appears in the logs:

    Apr 03 09:26:34 bean /usr/lib/gdm3/gdm-x-session[3709]: /etc/gdm3/Xsession: Beginning session setup...
    Apr 03 09:26:34 bean /usr/lib/gdm3/gdm-x-session[3709]: dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1001/bus
    Apr 03 09:26:34 bean /usr/lib/gdm3/gdm-x-session[3709]: dbus-update-activation-environment: setting DISPLAY=:0
    Apr 03 09:26:34 bean /usr/lib/gdm3/gdm-x-session[3709]: dbus-update-activation-environment: setting XAUTHORITY=/run/user/1001/gdm/Xauthority
    Apr 03 09:26:34 bean /usr/lib/gdm3/gdm-x-session[3709]: Xsession: unsupported number of arguments (5); falling back to default session.

I have amended the /etc/X11/Xsession.d/20x11-common_process-args script
to also print the passed arguments, and they are:

    GDK_BACKEND based on session type

I'm not sure where to look next ...

Kind regards,
Matijs

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_IE.utf8, LC_CTYPE=en_IE.utf8 (charmap=UTF-8), LANGUAGE=en_IE.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gdm3 depends on:
ii  accountsservice                       0.6.45-2
ii  adduser                               3.118
ii  dconf-cli                             0.30.1-2
ii  dconf-gsettings-backend               0.30.1-2
ii  debconf [debconf-2.0]                 1.5.71
ii  gir1.2-gdm-1.0                        3.32.0-1
ii  gnome-session [x-session-manager]     3.30.1-2
ii  gnome-session-bin                     3.30.1-2
ii  gnome-settings-daemon                 3.30.2-3
ii  gnome-shell                           3.30.2-3
ii  gnome-terminal [x-terminal-emulator]  3.30.2-2
ii  gsettings-desktop-schemas             3.28.1-1
ii  libaccountsservice0                   0.6.45-2
ii  libaudit1                             1:2.8.4-2
ii  libc6                                 2.28-8
ii  libcanberra-gtk3-0                    0.30-7
ii  libcanberra0                          0.30-7
ii  libgdk-pixbuf2.0-0                    2.38.1+dfsg-1
ii  libgdm1                               3.32.0-1
ii  libglib2.0-0                          2.58.3-1
ii  libglib2.0-bin                        2.58.3-1
ii  libgtk-3-0                            3.24.5-1
ii  libkeyutils1                          1.6-6
ii  libpam-modules                        1.3.1-5
ii  libpam-runtime                        1.3.1-5
ii  libpam-systemd                        241-2
ii  libpam0g                              1.3.1-5
ii  librsvg2-common                       2.44.10-1
ii  libselinux1                           2.8-1+b1
ii  libsystemd0                           241-2
ii  libwrap0                              7.6.q-28
ii  libx11-6                              2:1.6.7-1
ii  libxau6                               1:1.0.8-1+b2
ii  libxcb1                               1.13.1-2
ii  libxdmcp6                             1:1.1.2-3
ii  lsb-base                              10.2019031300
ii  mutter [x-window-manager]             3.30.2-6
ii  openbox [x-window-manager]            3.6.1-8
ii  policykit-1                           0.105-25
ii  procps                                2:3.3.15-2
ii  rxvt-unicode [x-terminal-emulator]    9.22-6
ii  tilix [x-terminal-emulator]           1.8.9-1
ii  ucf                                   3.0038+nmu1
ii  x11-common                            1:7.7+19
ii  x11-xserver-utils                     7.7+8
ii  xterm [x-terminal-emulator]           344-1

Versions of packages gdm3 recommends:
ii  at-spi2-core    2.30.0-7
ii  desktop-base    10.0.0
ii  x11-xkb-utils   7.7+4
ii  xserver-xephyr  2:1.20.4-1
ii  xserver-xorg    1:7.7+19
ii  zenity          3.30.0-2

Versions of packages gdm3 suggests:
pn  gnome-orca            <none>
pn  libpam-fprintd        <none>
ii  libpam-gnome-keyring  3.28.2-5

-- Configuration Files:
/etc/gdm3/daemon.conf changed:
[daemon]
[security]
[xdmcp]
[chooser]
[debug]


-- debconf information:
  gdm3/daemon_name: /usr/sbin/gdm3
* shared/default-x-display-manager: gdm3