9.10 Ubuntu - Unable to login with gdm after recent update

[Lothsahn]

My parents are running Ubuntu 9.10 on their computer, and upgraded from 9.04 a couple weeks ago. All has been well until today.

After the recent updates that I installed today, I am unable to login with GDM on my parents computer. I enter the login information and it kills my x11vnc session and when I reconnect it's at the GDM login screen still.

I am connecting to their computer using x11vnc, and I've always been able to login with their credentials before. This problem only started occurring after the recent update (of which GDM was one package that was updated).

I am also able to successfully login to their computer using SSH with the same login details, so I know the user and password are intact and correct.

I would be happy to provide any log files or anything, but I don't seen any obvious error messages. If you want or need certain files, please let me know.

[krunge]

After the recent updates that I installed today, I am unable to login with GDM on my parents computer. I enter the login information and it kills my x11vnc session and when I reconnect it's at the GDM login screen still.

It sounds like the X server is crashing. Look at /var/log/Xorg.0.log.old, etc. for any signs of a crash.

Have a look here to see if you have having the same problem:

http://ubuntuforums.org/showpost.php?p=6132263&postcount=13

If you didn't say the GDM login was still up, I would not have thought the X server crashed. Recent GDM now enforces KillInitClients=true (used to be configurable in gdm.conf) and so tries to kill x11vnc after the user has logged in (workaround in place upstream in x11vnc version 0.9.9) Your description does not fit this, but consider it just in case.

[Lothsahn]

Krunge:

Checked the recommend log file and I see no signs of a crash of the X server. I found this other thread which you had posted resolutions on:
http://ubuntuforums.org/showthread.php?p=8447619#post8447619

I downloaded http://x11vnc.sourceforge.net/dev/x11vnc-0.9.9_TEST_i686-Linux from your website, and it resolved the issue. Now when I login, x11vnc does not stop running, and ubuntu logs in successfully. So I think this is the same issue as on the other thread.

However, if I'm on the desktop and I click logoff, I get:
caught XIO error:
05/12/2009 21:23:07 deleted 32 tile_row polling images.

Although this is not as severe as the login problem, as I can login and logoff, it would be nice if x11vnc did not terminate when I logoff.

Thanks,
Lothsahn

[krunge]

However, if I'm on the desktop and I click logoff, I get:
caught XIO error:
05/12/2009 21:23:07 deleted 32 tile_row polling images.

Although this is not as severe as the login problem, as I can login and logoff, it would be nice if x11vnc did not terminate when I logoff.

This is the intended behavior. Your X server is in the process of exiting and has closed its socket with x11vnc (hence the I/O error.) x11vnc cleans up a lttle bit (removes the shared memory polling images) and exits as well.

There is not much point to him waiting around to see if he might be able to connect to a new X server that happens to start up. That's what the /etc/gdm/Init/Default is for.

If you didn't want to use /etc/gdm/Init/Default, x11vnc has a cheesy '-loop' option that will keep trying to restart itself periodically to connect to the X display in case one comes back (n.b. the Xauthority likely needs to be the same for him to be able to connect.) In some rare cases that might be a better way to go.

However, it sounds as though you want the VNC connection to stay up during this period, I guess showing a frozen version of the last screen and ignoring all mouse and keyboard input. That would require some changes, and I am not sure how useful it would be...

[Lothsahn]

Not sure how useful it would be either. I didn't realize the implementation details of "The x server terminates or is still running, etc". All I know is that from the monitor, it's a seemless transition--the logout occurs and then the login screen appears. From a remote user, it kills the session.

Like I said, not a big deal. I'll look into the polling thing or putting the startup in the gdm Init scripts. That's probably plenty good enough.

[krunge]

Not sure how useful it would be either. I didn't realize the implementation details of "The x server terminates or is still running, etc". All I know is that from the monitor, it's a seemless transition--the logout occurs and then the login screen appears. From a remote user, it kills the session.

Like I said, not a big deal. I'll look into the polling thing or putting the startup in the gdm Init scripts. That's probably plenty good enough.
Yes, it seems all installations have the Xserver process die when the X session ends (user logout). It seems possible to configure this, see the Xserver(1) man page '-noreset' option. But like I say, this is not the standard config and so id rarely used. And even still, the XAUTHORITY changes between sessions (otherwise the previous user could connect to the next user's desktop), so that would cause problems.

There are a couple of hacks that come to mind to let the X server restart, x11vnc has the -reopen option (an early attempt to avoid the problems with GDM killing it), but that could be unstable and is only intended for one or two restarts, not staying running for many restarts. Another is the '-rawfb console' which will work if there is a framebuffer module loaded in the kernel, but that will likely not provide reliable mouse and keystroke insertion.

So in general I think someone should just rig up a restart loop/script somehow (reverse connection comes to mind) if they really want to stay attached between user logins.