Bug#359057: gdm: heisenbug when using xdmcp

[James Harper]

Package: gdm
Version: 2.8.0.6-2
Severity: normal

Not sure that this is actually a gdm bug. I did a dist-upgrade on my Etch system to pick up the latest patches, and now I can't log in using xdmcp (probably not at the console either but the server is headless so I can't test it). Everything just hangs with a disabled username and password field at the login screen after entering the username and password (correctly or incorrectly).

The dist-upgrade upgraded to 2.13.0.10-2 which is where i first saw the problem, but even after a downgrade to 2.8.0.6-2 the problem persists, so either this isn't a gdm problem, or it is a gdm bug introduced by an upgrade to another package.

As soon as I switch on debugging in gdm.conf, it works perfectly (hence heisenbug).

-- System Information:
Debian Release: testing/unstable
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.15-1-686-smp
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages gdm depends on:
ii  adduser                  3.85            Add and remove users and groups
ii  debconf [debconf-2.0]    1.4.71          Debian configuration management sy
ii  gksu                     1.3.6-1         graphical frontend to su
ii  gnome-session            2.12.0-4        The GNOME 2 Session Manager
ii  gnome-terminal [x-termin 2.12.0-2        The GNOME 2 terminal emulator appl
ii  libart-2.0-2             2.3.17-1        Library of functions for 2D graphi
ii  libatk1.0-0              1.10.3-1        The ATK accessibility toolkit
ii  libattr1                 2.4.31-1        Extended attribute shared library
ii  libaudiofile0            0.2.6-6         Open-source version of SGI's audio
ii  libbonobo2-0             2.10.1-1        Bonobo CORBA interfaces library
ii  libbonoboui2-0           2.10.1-2        The Bonobo UI library
ii  libbz2-1.0               1.0.3-2         high-quality block-sorting file co
ii  libc6                    2.3.6-3         GNU C Library: Shared libraries an
ii  libcroco3                0.6.1-1         a generic Cascading Style Sheet (C
ii  libdmx1                  6.9.0.dfsg.1-4  Distributed Multihead X client lib
ii  libesd0                  0.2.36-3        Enlightened Sound Daemon - Shared 
ii  libgconf2-4              2.12.1-12       GNOME configuration database syste
ii  libgcrypt11              1.2.2-1         LGPL Crypto library - runtime libr
ii  libglade2-0              1:2.5.1-2       library to load .glade files at ru
ii  libglib2.0-0             2.8.6-1         The GLib library of C routines
ii  libgnome-keyring0        0.4.8-1         GNOME keyring services library
ii  libgnome2-0              2.12.0.1-5      The GNOME 2 library - runtime file
ii  libgnomecanvas2-0        2.12.0-2        A powerful object-oriented display
ii  libgnomeui-0             2.12.1-1        The GNOME 2 libraries (User Interf
ii  libgnomevfs2-0           2.12.2-5        GNOME virtual file-system (runtime
ii  libgnutls11              1.0.16-14       GNU TLS library - runtime library
ii  libgpg-error0            1.2-1           library for common error values an
ii  libgsf-1-113             1.13.3-1        Structured File Library - runtime 
ii  libgtk2.0-0              2.8.13-1        The GTK+ graphical user interface 
ii  libice6                  6.9.0.dfsg.1-4  Inter-Client Exchange library
ii  libjpeg62                6b-12           The Independent JPEG Group's JPEG 
ii  liborbit2                1:2.12.4-1      libraries for ORBit2 - a CORBA ORB
ii  libpam-modules           0.79-3.1        Pluggable Authentication Modules f
ii  libpam-runtime           0.79-3.1        Runtime support for the PAM librar
ii  libpam0g                 0.79-3.1        Pluggable Authentication Modules l
ii  libpango1.0-0            1.10.4-1        Layout and rendering of internatio
ii  libpopt0                 1.7-5           lib for parsing cmdline parameters
ii  librsvg2-2               2.12.7-5        SAX-based renderer library for SVG
ii  libselinux1              1.28-4          SELinux shared libraries
ii  libsm6                   6.9.0.dfsg.1-4  X Window System Session Management
ii  libtasn1-2               0.2.17-1        Manage ASN.1 structures (runtime)
ii  libwrap0                 7.6.dbs-9       Wietse Venema's TCP wrappers libra
ii  libx11-6                 6.9.0.dfsg.1-4  X Window System protocol client li
ii  libxau6                  6.9.0.dfsg.1-4  X Authentication library
ii  libxdmcp6                6.9.0.dfsg.1-4  X Display Manager Control Protocol
ii  libxext6                 6.9.0.dfsg.1-4  X Window System miscellaneous exte
ii  libxi6                   6.9.0.dfsg.1-4  X Window System Input extension li
ii  libxinerama1             6.9.0.dfsg.1-4  X Window System multi-head display
ii  libxml2                  2.6.23.dfsg.2-2 GNOME XML library
ii  metacity [x-window-manag 1:2.12.3-3      A lightweight GTK2 based Window Ma
ii  multi-gnome-terminal [x- 1.6.2-11.1      Enhanced the GNOME Terminal
ii  twm [x-window-manager]   6.9.0.dfsg.1-4  Tab window manager
ii  xbase-clients            6.9.0.dfsg.1-4  miscellaneous X clients
ii  xlibs                    6.9.0.dfsg.1-4  X Window System client libraries m
ii  xterm [x-terminal-emulat 208-3.1         X terminal emulator
ii  zlib1g                   1:1.2.3-9       compression library - runtime

Versions of packages gdm recommends:
ii  dialog                    1.0-20060221-1 Displays user-friendly dialog boxe
pn  gdm-themes                <none>         (no description available)
ii  whiptail                  0.51.6-31      Displays user-friendly dialog boxe
ii  zenity                    2.12.1-2       Display graphical dialog boxes fro

-- debconf information:
  gdm/daemon_name: /usr/bin/gdm
* shared/default-x-display-manager: gdm