Title: Frequently random Plasma crashes

What I was doing when the application crashed:
Since a week, Plasma is crashing randomly. Usually it crashes when the CPU is heavily loaded. 
For example I'm compiling KDE from trunk and doing a lot of other operations... I'm not able to find a pattern to reproduce the crash.

 -- Application and System information:
Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.2.71 (KDE 4.2.71 (KDE 4.3 >= 20090428))
Qt Version: 4.5.0
Operating System: Linux 2.6.29-ARCH x86_64

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 0 (LWP 3287)]

Thread 2 (Thread 0x7f948785b950 (LWP 3570)):
#0  0x00007f94a20cfd69 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f94a2340d19 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#2  0x00007f94a5b14e1c in ?? () from /usr/lib/libQtNetwork.so.4
#3  0x00007f94a233fd22 in ?? () from /usr/lib/libQtCore.so.4
#4  0x00007f94a20cbfc7 in start_thread () from /lib/libpthread.so.0
#5  0x00007f94a169a5dd in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f94a7156790 (LWP 3287)):
[KCrash Handler]
#5  TaskManager::Task::window (this=0x0) at /mnt/archivio/KDE4/src/kdebase/workspace/libs/taskmanager/task.cpp:355
#6  0x00007f948994fb38 in AbstractTaskItem::timerEvent (this=0x1cb9720, event=<value optimized out>) at /mnt/archivio/KDE4/src/kdebase/workspace/plasma/applets/tasks/abstracttaskitem.cpp:399
#7  0x00007f94a2437e43 in QObject::event () from /usr/lib/libQtCore.so.4
#8  0x00007f94a31430db in QGraphicsWidget::event () from /usr/lib/libQtGui.so.4
#9  0x00007f94a2b3070d in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#10 0x00007f94a2b388fa in QApplication::notify () from /usr/lib/libQtGui.so.4
#11 0x00007f94a5451ceb in KApplication::notify (this=0x1195030, receiver=0x1cb9720, event=0x7fffaf298ed0) at /mnt/archivio/KDE4/src/kdelibs/kdeui/kernel/kapplication.cpp:307
#12 0x00007f94a242818c in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#13 0x00007f94a2455356 in ?? () from /usr/lib/libQtCore.so.4
#14 0x00007f94a245187d in ?? () from /usr/lib/libQtCore.so.4
#15 0x00007f949dcb701a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#16 0x00007f949dcba6e0 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#17 0x00007f949dcba87c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#18 0x00007f94a24517df in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#19 0x00007f94a2bc774f in ?? () from /usr/lib/libQtGui.so.4
#20 0x00007f94a2426a32 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#21 0x00007f94a2426dfd in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#22 0x00007f94a24290c4 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#23 0x00007f94a6e368ab in kdemain (argc=1, argv=0x7fffaf299488) at /mnt/archivio/KDE4/src/kdebase/workspace/plasma/shells/desktop/main.cpp:50
#24 0x00007f94a15e9546 in __libc_start_main () from /lib/libc.so.6
#25 0x00000000004007f9 in _start ()