I'm having a problem with KDM: just after I type my password and hit enter, the screen goes black for a second and then the login screen returns. Xorg.0.log has no errors in it; it reports simply that it exits OK. kdm.log also has nothing really in it (though I've included --debug 399 output below). I'm not sure what changed from the last time I used KDM; I've been logged in for months and applied several system updates in that time.

I'm on KDE 4.10.5 on a stable gentoo system. Running 'xinit /usr/bin/startkde' gets me to a kde desktop just fine, FWIW. It's only kdm that seems to be broken. I've reinstalled kdm and ran revdep-rebuild (which didn't find anything) to no avail.

Log output: http://pastebin.com/w9piKTpT

Is your desktop session in KDM set to "previously used"? If so, try changing it to "KDE Plasma Workspace".

Neither "KDE Plasma Workspace" nor the failsafe equivalent produces different results. Even selecting TWM fails the same way.

After attempting a normal login, is anything of relevance output to ~/.xsession-errors?

I get literally this string (I did not ellipsize):

/usr/share/config/kdm/Xsession:59: bad math expression: operand expected at `/etc/X11/x...'

Line 59 mentioned above is the for loop here:

Code: Select all

# run all system xinitrc shell scripts.
if [ -d /etc/X11/xinit/xinitrc.d ]; then
    for i in /etc/X11/xinit/xinitrc.d/* ; do
        if [ -x "$i" ]; then
            . "$i"
        fi
    done
fi


That shell code looks reasonable to me. Just in case it's misreporting some error from sourcing the xinitrc.d files, I've tried -x'ing all of the files in /etc/X11/xinit/xinitrc.d/ with no change.

So, it turns out that this:

Code: Select all

 bad math expression: operand expected

is a zsh error message. Why would my xsession stuff be executing with zsh (my user's shell) instead of bash? Is this something that could be fixed by going from 4.10 to 4.11?

Looks like this bug might be related: https://bugs.kde.org/show_bug.cgi?id=322505

The ubuntu folks found the problem too: https://bugs.launchpad.net/ubuntu/+sour ... +bug/13965

KDE does not provide the /etc/kde4/kdm/Xsession file, it must come from your distribution.
I would recommend adding "#!/bin/bash" to the top of that file (which should hopefully force the use of bash)

The file already has the #! /bin/sh shebang, so it must be being sourced by some other script, not executed. I'll look into how my distro (gentoo) packages it.

In many distributions (no idea about Gentoo) /bin/sh is not bash, but another shell such as dash - so this may be worth checking.

It's bash on Gentoo.