Application: kwin (4.8.2 (4.8.2))
KDE Platform Version: 4.8.2 (4.8.2)
Qt Version: 4.8.1
Operating System: Linux 3.2.0-23-generic x86_64
Distribution: Ubuntu 12.04 LTS

-- Information about the crash:
I am contacting my Ubuntu computer from a Windows system using NX connection (connection software from Nomachine 
http://www.nomachine.com/). After conection I get this error report. This error is new with the Ubuntu 12.04 beta installation.

After the error message, the connection seems to be working. (I am running the crash reporting assitant through the same connection.) The only additional problem was that automatic debug library installation did fail, it apparently did ot succed in creating the required authorization window.

I am using KDE, because I have  problems with Gnome in this configuration. The Gnome problem is caused by the window manager detecting my Nvidia graphics card, and assuming that the highend features are also available on the NX connection, when they are not available.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f2262ba97c0 (LWP 17057))]

Thread 2 (Thread 0x7f224544b700 (LWP 17062)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f225ee7a222 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f225ee7a259 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f225e625b74 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#4  0x00007f2256c03e9a in start_thread (arg=0x7f224544b700) at pthread_create.c:308
#5  0x00007f22623c14bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f2262ba97c0 (LWP 17057)):
[KCrash Handler]
#6  mUSABLe (mem=0x1) at malloc.c:4651
#7  __malloc_usable_size (m=0x1) at malloc.c:3379
#8  0x00007f225e626853 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#9  0x00007f22569fac01 in ?? () from /usr/lib/nvidia-current/tls/libnvidia-tls.so.295.40
#10 0x00007f225fe06819 in XFree (data=<optimized out>) at ../../src/XlibInt.c:1701
#11 0x00007f225f9ae2ee in XRRUpdateConfiguration (event=0x7fffabd8c1f0) at ../../src/Xrandr.c:446
#12 0x00007f22626f8a30 in KWin::Workspace::workspaceEvent (this=0x2127960, e=0x7fffabd8c1f0) at ../../kwin/events.cpp:460
#13 0x00007f22626ea288 in KWin::Application::x11EventFilter (this=0x7fffabd8c500, e=0x7fffabd8c1f0) at ../../kwin/main.cpp:359
#14 0x00007f225cec9b85 in qt_x11EventFilter (ev=0x7fffabd8c1f0) at kernel/qapplication_x11.cpp:441
#15 qt_x11EventFilter (ev=0x7fffabd8c1f0) at kernel/qapplication_x11.cpp:429
#16 0x00007f225ced8f98 in QApplication::x11ProcessEvent (this=0x7fffabd8c500, event=0x7fffabd8c1f0) at kernel/qapplication_x11.cpp:3444
#17 0x00007f225cf03b4a in QEventDispatcherX11::processEvents (this=0x1f5fad0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#18 0x00007f225dad6c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#19 0x00007f225dad6ed7 in QEventLoop::exec (this=0x7fffabd8c440, flags=...) at kernel/qeventloop.cpp:204
#20 0x00007f225dadbf67 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#21 0x00007f22626eca06 in kdemain (argc=<optimized out>, argv=<optimized out>) at ../../kwin/main.cpp:541
#22 0x00007f22622f076d in __libc_start_main (main=0x400640 <main(int, char**)>, argc=1, ubp_av=0x7fffabd8cc28, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffabd8cc18) at libc-start.c:226
#23 0x0000000000400671 in _start ()

Reported using DrKonqi