Version:           4.3.80 (KDE 4.3.80 (KDE 4.4 Beta1)) "release 197" (using Devel)
Compiler:          gcc 
OS:                Linux
Installed from:    Compiled sources

I get the following Plasma desktop crash frequently:

---
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f7ca2bb87f0 (LWP 24785))]

Thread 6 (Thread 0x7f7c81f3c910 (LWP 24786)):
#0  0x00007f7ca234a049 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f7ca25d566b in wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f7c9e9423ec in QHostInfoAgent::run (this=0xbd64c0) at kernel/qhostinfo.cpp:252
#4  0x00007f7ca25d46b5 in QThreadPrivate::start (arg=0xbd64c0) at thread/qthread_unix.cpp:244
#5  0x00007f7ca234565d in start_thread () from /lib64/libpthread.so.0
#6  0x00007f7c9fc0e14d in clone () from /lib64/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 5 (Thread 0x7f7c804a2910 (LWP 25225)):
#0  0x00007f7ca234a049 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f7ca25d566b in wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f7c97915826 in ?? () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f7c97917edb in ?? () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f7c9791638f in ?? () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f7c979167e8 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f7ca25d46b5 in QThreadPrivate::start (arg=0xf3de20) at thread/qthread_unix.cpp:244
#8  0x00007f7ca234565d in start_thread () from /lib64/libpthread.so.0
#9  0x00007f7c9fc0e14d in clone () from /lib64/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7f7c7fca1910 (LWP 25226)):
#0  0x00007f7ca234a049 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f7ca25d566b in wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f7c97915826 in ?? () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f7c97917edb in ?? () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f7c97917ef4 in ?? () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f7c9791638f in ?? () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f7c979167e8 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#8  0x00007f7ca25d46b5 in QThreadPrivate::start (arg=0xc57630) at thread/qthread_unix.cpp:244
#9  0x00007f7ca234565d in start_thread () from /lib64/libpthread.so.0
#10 0x00007f7c9fc0e14d in clone () from /lib64/libc.so.6
#11 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f7c7f4a0910 (LWP 25227)):
#0  0x00007f7ca234a049 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f7ca25d566b in wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f7c97915826 in ?? () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f7c97917edb in ?? () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f7c9791638f in ?? () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f7c979167e8 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f7ca25d46b5 in QThreadPrivate::start (arg=0x6ce6e0) at thread/qthread_unix.cpp:244
#8  0x00007f7ca234565d in start_thread () from /lib64/libpthread.so.0
#9  0x00007f7c9fc0e14d in clone () from /lib64/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f7c7ec9f910 (LWP 25228)):
#0  0x00007f7ca234a049 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f7ca25d566b in wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f7c97915826 in ?? () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f7c97917edb in ?? () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f7c9791638f in ?? () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f7c979167e8 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f7ca25d46b5 in QThreadPrivate::start (arg=0xc67840) at thread/qthread_unix.cpp:244
#8  0x00007f7ca234565d in start_thread () from /lib64/libpthread.so.0
#9  0x00007f7c9fc0e14d in clone () from /lib64/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f7ca2bb87f0 (LWP 24785)):
[KCrash Handler]
#5  QGraphicsScenePrivate::processDirtyItemsRecursive (this=0x866b20, item=0xd06a00, dirtyAncestorContainsChildren=false, parentOpacity=0) at graphicsview/qgraphicsscene.cpp:4895
#6  0x00007f7ca098455d in QGraphicsScenePrivate::_q_processDirtyItems (this=0x866b20) at graphicsview/qgraphicsscene.cpp:466
#7  0x00007f7ca0984ba2 in QGraphicsScene::qt_metacall (this=0x8668b0, _c=InvokeMetaMethod, _id=<value optimized out>, _a=0xd39080) at .moc/release-shared/moc_qgraphicsscene.cpp:130
#8  0x00007f7c9945e765 in Plasma::Corona::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib64/libplasma.so.3
#9  0x00007f7c95cad8a3 in DesktopCorona::qt_metacall (this=0x866b20, _c=13658624, _id=0, _a=0x0) at /usr/src/debug/kdebase-workspace-4.3.80/build/plasma/desktop/shell/desktopcorona.moc:78
#10 0x00007f7ca26d7209 in QObject::event (this=0x8668b0, e=0x1823c50) at kernel/qobject.cpp:1260
#11 0x00007f7ca0980bb0 in QGraphicsScene::event (this=0x8668b0, event=0x1823c50) at graphicsview/qgraphicsscene.cpp:3450
#12 0x00007f7ca0363bcc in QApplicationPrivate::notify_helper (this=0x678170, receiver=0x8668b0, e=0x1823c50) at kernel/qapplication.cpp:4242
#13 0x00007f7ca036a1ed in QApplication::notify (this=0x66a910, receiver=0x8668b0, e=0x1823c50) at kernel/qapplication.cpp:4125
#14 0x00007f7ca10478f6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#15 0x00007f7ca26c753c in QCoreApplication::notifyInternal (this=0x66a910, receiver=0x8668b0, event=0x1823c50) at kernel/qcoreapplication.cpp:704
#16 0x00007f7ca26c9cb7 in sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:215
#17 QCoreApplicationPrivate::sendPostedEvents (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.cpp:1345
#18 0x00007f7ca26f0fd3 in sendPostedEvents () at kernel/qcoreapplication.h:220
#19 postEventSourceDispatch () at kernel/qeventdispatcher_glib.cpp:276
#20 0x00007f7c9f089dde in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#21 0x00007f7c9f08d7a8 in ?? () from /usr/lib64/libglib-2.0.so.0
#22 0x00007f7c9f08d8d0 in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#23 0x00007f7ca26f0b13 in QEventDispatcherGlib::processEvents (this=0x677bc0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:407
#24 0x00007f7ca041094e in QGuiEventDispatcherGlib::processEvents (this=0x866b20, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#25 0x00007f7ca26c5e52 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#26 0x00007f7ca26c622c in QEventLoop::exec (this=0x7fffa4032ab0, flags=) at kernel/qeventloop.cpp:201
#27 0x00007f7ca26c9f7b in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#28 0x00007f7c95cb4ac2 in kdemain (argc=<value optimized out>, argv=<value optimized out>) at /usr/src/debug/kdebase-workspace-4.3.80/plasma/desktop/shell/main.cpp:112
#29 0x0000000000406f88 in launch (argc=1, _name=<value optimized out>, args=<value optimized out>, cwd=<value optimized out>, envc=0, envs=<value optimized out>, reset_env=false, tty=0x0, 
    avoid_loops=false, startup_id_str=0x40a4d5 "0") at /usr/src/debug/kdelibs-4.3.80/kinit/kinit.cpp:705
#30 0x0000000000407c80 in handle_launcher_request (sock=7, who=<value optimized out>) at /usr/src/debug/kdelibs-4.3.80/kinit/kinit.cpp:1197
#31 0x0000000000408131 in handle_requests (waitForPid=0) at /usr/src/debug/kdelibs-4.3.80/kinit/kinit.cpp:1390
#32 0x0000000000408dfa in main (argc=4, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/kdelibs-4.3.80/kinit/kinit.cpp:1825
---

Hopefully there were enough debug symbols installed to locate the problem.