Infinite loop in GUI login

phcorrigan · Post by **phcorrigan** » 2011/08/02 04:54:13

I just installed CentOS 6 64-bit with KDE. Everything was running smoothy through updates, multiple reboots, etc. Since about an hour ago I can no longer log in in a normal mode. Using the GUI login with KDE I can log in, the system will begin setting up the desktop and then the screen goes black and returns me to the login screen. It is the same for different users (root and the only other user defined). When I select console login from the menu I get a blank screen with a white bar at the bottom with "CentOS Linux 6.0" at the right and no prompt. I can login in failsafe mode, however.

Any ideas on what might be the cause and resolution?

Thanks.

r_hartman · Post by **r_hartman** » 2011/08/02 10:14:00

Welcome to the CentOS fora; new users are encouraged to follow the links in my signature.

I do not use KDE, but this sounds like a display driver issue, causing gdm to crash. Check /var/log/messages.
From a console session, see what was updated in /var/log/yum.log, and try and isolate updates to X, gdm, videodrivers, etc, and do a downgrade of those.

Alternatively, see if [url=http://elrepo.org]ELRepo[/url] has a driver for your videocard and install that.

EDIT: the bar at the bottom is the boot progress bar.You can get rid of that by hitting 'Esc' when the box starts booting, or by removing 'rhgb quiet' from the kernel line in grub. You can then see what's going on.

pschaff · Post by **pschaff** » 2011/08/02 18:10:15

Since the GUI login works I would tend to suspect a SELinux problem rather than a graphics driver problem. I'd try booting with "selinux=0" on the command line, or changing to a virtual console with "Ctrl-Alt-Fx" where x is in 2 3 4 5 6, logging in as root, and doing "setenforce 0". If that helps then relabeling the filesystem may be indicated.

r_hartman · Post by **r_hartman** » 2011/08/03 06:44:03

Good point. I keep forgetting selinux is by default set to enforcing in CentOS6, as I haven't had a single issue with it yet. In CentOS5 I had it set to permissive as enforcing gave me too many issues, although documentation gets better and troubleshooting easier, and in CentOS5.6 the policies seem to be better as well, as I do not see that many warnings anymore.

phcorrigan · Post by **phcorrigan** » 2011/08/04 16:48:30

I found a "fix" on the Kubuntu forums (delete ~/dmrc) but that was only temporary. The real fix was to remove KDE and install GNOME. I still don't know the root cause but removing KDE seems to have fixed the problem.

CentOS