Re: [gdm-list] handled=false xservers broken in 2.20.0 vs. 2.18.1

["Michael Pardee" <gdm-list groovix com>]

Hello, from: http://open-sense.com/downloads/gdm/syslog20.defaultconf
it looks like 6774 is another gdm child process:
grep 6774 syslog20.defaultconf
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: gdm_display_manage: Forked slave: 6774
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: xdmcp/PingIntervalSeconds=15
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_slave_start: Starting
slave process for :0
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_slave_start: Loop Thingie
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: xdmcp/PingIntervalSeconds=15
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Sending VT_NUM == -1 for slave 6774
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: Handling message: 'VT_NUM 6774 -1'
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_server_start: :0
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_auth_secure_display:
Setting up access for :0
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: daemon/ServAuthDir=/var/lib/gdm
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_auth_secure_display:
Setting up access
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: debug/Enable=false
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_auth_secure_display:
Setting up access for :0 - 1 entries
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: debug/Enable=false
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Sending COOKIE == <secret>
for slave 6774
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: Handling message: 'COOKIE 6774 34...'
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: debug/Enable=false
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Sending AUTHFILE == <secret>
for slave 6774
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: Handling message: 'AUTHFILE
6774 /var/lib/gdm/:0.Xauth'
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: daemon/VTAllocation=true
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: daemon/FirstVT=7
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: security/DisallowTCP=true
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Forking X server process
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_server_spawn: Forked
server on pid 6781
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: do_server_wait: Before
mainloop waiting for server
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: daemon/GdmXserverTimeout=10
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Attempting to parse key
string: daemon/GdmXserverTimeout=10
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_server_start: After
mainloop waiting for server
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_server_start: Completed :0!
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Sending VT_NUM == 14 for slave 6774
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: Handling message: 'VT_NUM 6774 14'
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: Sending XPID == 6781 for slave 6774
Nov  2 16:00:30 ubuntu gdm[6773]: DEBUG: Handling message: 'XPID 6774 6781'
Nov  2 16:00:30 ubuntu gdm[6774]: DEBUG: gdm_slave_run: Opening display :0
Nov  2 16:00:31 ubuntu gdm[6773]: WARNING: gdm_cleanup_children: child
6774 crashed of signal 11

--

I can start the X server just fine with the exact same parameters from
gdm 2.18 or the command line, so I don't think the x server itself is
crashing, unless it has something to do with the way gdm 2.20 is
starting it. What's the best way to try to figure out why the gdm
slave is segfaulting?

Michael Pardee
Open Sense Solutions LLC
http://open-sense.com
888-323-1742

On 11/2/07, Brian Cameron <Brian Cameron sun com> wrote:
> Michael:
>
> What process corresponds to 6774?  Any ideas why process 6774 is dying
> with a SEGV (signal 11)?  GDM is probably doing the right thing by
> trying to restart if it notices a child is segfaulting.
>
> Brian
>
>
> > I can't tell what is going on from the debugging information.  It
> > forks the x server, and then it looks like it dies 1 second later:
> > Nov  2 16:00:30 ubuntu gdm[6781]: DEBUG: gdm_server_spawn: '/usr/bin/X
> > :0 -br -audit 0 -auth /var/lib/gdm/:0.Xauth -nolisten tcp vt14'
> > ...
> > Nov  2 16:00:31 ubuntu gdm[6773]: DEBUG: mainloop_sig_callback: Got signal 17
> > Nov  2 16:00:31 ubuntu gdm[6773]: WARNING: gdm_cleanup_children: child
> > 6774 crashed of signal 11
> >
> > Here are files with the default gdm.conf (Ubuntu 7.10) except for handled=false
> > http://open-sense.com/downloads/gdm/syslog20.defaultconf
> > http://open-sense.com/downloads/gdm/gdm.conf
> >
> > And just in case anyone is curious here are the original multi-user files:
> > http://open-sense.com/downloads/gdm/syslog20.xephyr
> > http://open-sense.com/downloads/gdm/syslog18.xephyr
> > http://open-sense.com/downloads/gdm/gdm_xephyr.conf
> >
> > If any other information would be useful please let me know.
> > Thanks,
> > Michael Pardee
> > Open Sense Solutions LLC
> > http://open-sense.com
> > 888-323-1742
> >
> >
> > On 11/2/07, Brian Cameron <Brian Cameron sun com> wrote:
> >> Michael:
> >>
> >> This might well be a bug.  I'd recommend turning on debug in the
> >> GDM configuration, restarting GDM and allow it to fail, then
> >> send along the GDM-related debug output that gets sent to your syslog
> >> (/var/log/messages or /var/adm/messages depending on your OS).
> >>
> >> This might highlight why GDM thinks it needs to remanage the display
> >> in this case, and assist in debugging your situation.
> >>
> >> Brian
> >>
> >>
> >>> We've been using gdm 2.18.1 for a while now, and we just tried 2.20.0
> >>> in ubuntu 7.10 and our setup breaks horribly.   I went through the
> >>> changelog between 2.18 and 2.20, but it looks like A LOT has changed.
> >>> If someone could give any ideas on which of the changes may be causing
> >>> this problem that would be very helpful instead of trying lots of gdm
> >>> version in between 2.18 and 2.20.  Maybe we need different parameters
> >>> in the gdm.conf now?
> >>>
> >>> Basically, if you add handled=false to an x server in 2.20, gdm tries
> >>> to start it but it does not leave it up, and eventually you get the
> >>> "screen has shut down 6 times in 90 seconds" message.  Taking the
> >>> exact same setup and installing gdm 2.18, the handled=false xserver is
> >>> started and left up as desired.
> >>>
> >>> With 2.20 you can see the x server running briefly with ps, and
> >>> /var/log/gdm/* and /var/log/Xorg* look normal, it just seems that gdm
> >>> is "reaping" the xserver for some reason?
> >>>
> >>> example:
> >>> [server-Standard]
> >>> name=Standard server
> >>> command=/usr/bin/X -br -audit 0
> >>> flexible=false
> >>> handled=false
> >>>
> >>> You're probably wondering why are we trying to start an unhandled x
> >>> server?  We run one unhandled x server across many displays, and then
> >>> run xephyr on each display for multi-user capability.  While that does
> >>> introduce many other variables that could cause problems, the simplest
> >>> case of handled=false doesn't work with gdm 2.20.0.
> >>>
> >>> Any suggestions would be appreciated.
> >>>
> >>> Thank You,
> >>> Michael Pardee
> >>> Open Sense Solutions LLC
> >>> http://open-sense.com
> >>> 888-323-1742
> >>> _______________________________________________
> >>> gdm-list mailing list
> >>> gdm-list gnome org
> >>> http://mail.gnome.org/mailman/listinfo/gdm-list
> >>
>
>