kwin crash on second (and subsequent) login

[Robert Chalmas]

At boot time, the KDE session always opens successfully. If I log out and try to log in again, kwin crashes immediatly after entering my password and pressing enter, without displaying KDE desktop, instead I'm back to the login screen. The next attempt is always successful and the KDE session opens, but with the desktop effects disabled.

After opening System Settings, then Desktop Effects, I can see the message " OpenGL compositing (the default) has crashed KWin in the past." If I re-enable the desktop effects and log out, then try to log in again, the crash repeats as described above. This is 100% reproductible.

The only two ways to be able to log in without crash when the desktop effects are enabled are rebooting or killing the X-server.

This happens with kubuntu 11.10 (on a fresh install but also with all updates) and 12.04 alpha1, but this did not happen with kubuntu 11.04. This happens with both 32 bit and 64 bit versions.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: kde-window-manager 4:4.7.1-0ubuntu5
ProcVersionSignature: Ubuntu 3.0.0-14.23-generic-pae 3.0.9
Uname: Linux 3.0.0-14-generic-pae i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
Date: Mon Dec 12 10:34:43 2011
InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
 LANGUAGE=
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: kde-workspace
UpgradeStatus: No upgrade log present (probably fresh install)

[Robert Chalmas (robert-chalmas)]

A similar report was also posted upstream:
https://bugs.kde.org/show_bug.cgi?id=288897

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Aditya Mehrotra (mehrotra-ad)]

It seem to be fixed in the daily live on 12/25/2012 of kubuntu 12.04. Tested it using the live USB has not yet installed on the system.

[Michael Tsang (miklcct)]

maybe you can try TerminateServer=true in /etc/kde4/kdm/kdmrc

[Stefano Forli (ntropia)]

I encounter a similar behavior with my netbook (32-bit, Intel 945GSE), KDE 4.8.3 (Kubuntu).
At every login, performances are unbearably slow, despite the fact that the settings report the OpenGL mode as active.

To fix the problem I have to switch the compositing type to XRenderer, apply, then set it back to OpenGL. When I do this, I get prompted with the same message Robert reported for this bug.

By testing it with a freshly created user, I can trigger the bug even without having to logout first. I've tested it on the aforementioned netbook:
-log with the default Plasma Netbook mode (max performances, very fluid)
-switch to Plasma Desktop (still max performances, very fluid)
-In System Settings->Desktop Effects->All Effects change any of the plugins already activated (i.e. Desktop Grid) then press Apply (desktop extremely slow, kwin constantly at 100% CPU usage)
-switching back and forth between OpenGL and Xrenderer fixes the problem
-at the next login, the desktop will be very slow again.

[Stefano Forli (ntropia)]

I don't know if this can be related, but I've also monitored the kwinrc content and it seems that upon any setting changes, the files goes from 25 to ~250 lines (somehow understandable, but... hard to debug). Initially, the line setting the OpenGL backend ("Backend=OpenGL") is not present, but after the setting change described above, it shows up.