Upgrade Suse 10.3 to 11.3 and startup fails

Question

I upgraded my Suse 10.3 installation to 11.4 using the update option from a network installation disk. When the update was complete I was asked to reboot. When I did the reboot I am asked to login. This seemed a little strange as it used to automatically log me in. I login with either the root login or a user login that I have created on my system. As soon as it accepts my login it lists when I lasted logged in and that I have new mail and then gives me "module is unknown" and shows me the login prompt again.

I have no idea how to see what module is unknown. Is there a way to get more information about what the system is unhappy about? Would a new install instead of an update have been a better option?

I was unsure what I would lose on the disk if I did a new install.

Answer 1

“Module is unknown” sounds like an error from PAM. Given that you can log in but are chucked out immediately, I think that means that your authentication succeeds, but one of the required session modules is missing (disappeared in the upgrade).

As long as you have physical access to the box, not being able to log in is easily repaired. When you get to a bootloader prompt, select single user mode. You may need to press Space or Shift at the right time to get a bootloader prompt. In single user mode, you will boot to a simple password prompt that doesn't use PAM; enter the root password.

To repair your system, you need to comment out or remove the offending PAM module. I don't know exactly how PAM is organized under SuSE, but the configuration should be either in /etc/pam.conf or in /etc/pam.d/*, and you're looking for one of the lines that begin with session. Once you've found the culprit, run

openvt -s login

and try logging in on the new console. Press Alt+F1 to return to the first console. Once you're able to log in, you can switch back to the normal multi-user mode with init 2 (or whatever your default runlevel is, as indicated by grep initdefault /etc/inittab).

If you don't know which one is the offending PAM module, look in your logs (/var/log/*) for clues, or post the PAM configuration here.