Version:            (using Devel)
Installed from:    Compiled sources

If I create a new taskbar entry somehow (new window, etc), plasma has a chance of crashing. In my instance, it was a totally unique window, so no grouping should have been performed. I had two apps already in there, and when I started a third, *boom*. Its rather random and hard to reproduce.

Application: Plasma Workspace (plasma), signal SIGSEGV
[Current thread is 1 (Thread 0xb7f5e970 (LWP 28853))]

Thread 3 (Thread 0xacd59b90 (LWP 28858)):
#0  0x00110416 in __kernel_vsyscall ()
#1  0x0096dba5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0x0522dc96 in QWaitCondition::wait (this=0x84e2990, mutex=0x84e298c, time=4294967295) at /usr/src/kde4/src/qt-copy/src/corelib/thread/qwaitcondition_unix.cpp:88
#3  0x0071d02d in QHostInfoAgent::run (this=0x84e2980) at /usr/src/kde4/src/qt-copy/src/network/kernel/qhostinfo.cpp:247
#4  0x0522d1b2 in QThreadPrivate::start (arg=0x84e2980) at /usr/src/kde4/src/qt-copy/src/corelib/thread/qthread_unix.cpp:190
#5  0x0096a32f in start_thread (arg=<value optimized out>) at pthread_create.c:297
#6  0x04e5220e in clone () from /lib/libc.so.6

Thread 2 (Thread 0xac358b90 (LWP 28859)):
#0  0x00110416 in __kernel_vsyscall ()
#1  0x0096dba5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0x0522dc96 in QWaitCondition::wait (this=0x82b4790, mutex=0x82b478c, time=4294967295) at /usr/src/kde4/src/qt-copy/src/corelib/thread/qwaitcondition_unix.cpp:88
#3  0x0600f162 in RenderThread::run (this=0x82b4784) at /home/trever/Projects/kde/kdebase/workspace/plasma/wallpapers/image/renderthread.cpp:90
#4  0x0522d1b2 in QThreadPrivate::start (arg=0x82b4784) at /usr/src/kde4/src/qt-copy/src/corelib/thread/qthread_unix.cpp:190
#5  0x0096a32f in start_thread (arg=<value optimized out>) at pthread_create.c:297
#6  0x04e5220e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb7f5e970 (LWP 28853)):
[KCrash Handler]
#6  TaskManager::GroupManager::add (this=0x8480ed0, task={d = 0x87aa920}) at /opt/kde4/include/QtCore/qhash.h:815
#7  0x05f6723f in TaskManager::GroupManager::qt_metacall (this=0x8480ed0, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbfa94fbc)
    at /home/trever/Projects/kde/build/kdebase/workspace/libs/taskmanager/groupmanager.moc:87
#8  0x0532be21 in QMetaObject::activate (sender=0x8348808, from_signal_index=<value optimized out>, to_signal_index=4, argv=<value optimized out>)
    at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qobject.cpp:3001
#9  0x0532c4b2 in QMetaObject::activate (sender=0x8348808, m=0x5f95318, local_signal_index=0, argv=0xbfa94fbc) at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qobject.cpp:3071
#10 0x05f86b33 in TaskManager::TaskManager::taskAdded (this=0x8348808, _t1={d = 0x87aa920}) at /home/trever/Projects/kde/build/kdebase/workspace/libs/taskmanager/taskmanager.moc:147
#11 0x05f888ce in TaskManager::TaskManager::windowAdded (this=0x8348808, w=54525953) at /home/trever/Projects/kde/kdebase/workspace/libs/taskmanager/taskmanager.cpp:255
#12 0x05f88f2c in TaskManager::TaskManager::qt_metacall (this=0x8348808, _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xbfa9516c)
    at /home/trever/Projects/kde/build/kdebase/workspace/libs/taskmanager/taskmanager.moc:104
#13 0x0532be21 in QMetaObject::activate (sender=0x8228e48, from_signal_index=<value optimized out>, to_signal_index=5, argv=<value optimized out>)
    at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qobject.cpp:3001
#14 0x0532c4b2 in QMetaObject::activate (sender=0x8228e48, m=0xd117cc, local_signal_index=1, argv=0xbfa9516c) at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qobject.cpp:3071
#15 0x00caf4f3 in KWindowSystem::windowAdded (this=0x8228e48, _t1=54525953) at /home/trever/Projects/kde/build/kdelibs/kdeui/kwindowsystem.moc:118
#16 0x00cb1b39 in KWindowSystemPrivate::addClient (this=0x819d350, w=54525953) at /home/trever/Projects/kde/kdelibs/kdeui/windowmanagement/kwindowsystem_x11.cpp:229
#17 0x00cc0fa0 in NETRootInfo::update (this=0x819d364, dirty_props=0xbfa95328) at /home/trever/Projects/kde/kdelibs/kdeui/windowmanagement/netwm.cpp:2123
#18 0x00cc130e in NETRootInfo::event (this=0x819d364, event=0xbfa957cc, properties=0xbfa953a8, properties_size=5) at /home/trever/Projects/kde/kdelibs/kdeui/windowmanagement/netwm.cpp:2052
#19 0x00cb1f4d in KWindowSystemPrivate::x11Event (this=0x819d350, ev=0xbfa9576c) at /home/trever/Projects/kde/kdelibs/kdeui/windowmanagement/kwindowsystem_x11.cpp:136
#20 0x00b5d6d9 in KApplication::x11EventFilter (this=0x80d77f8, _event=0xbfa9576c) at /home/trever/Projects/kde/kdelibs/kdeui/kernel/kapplication.cpp:945
#21 0x0014e124 in PlasmaApp::x11EventFilter (this=0x80d77f8, event=0xbfa9576c) at /home/trever/Projects/kde/kdebase/workspace/plasma/shells/desktop/plasmaapp.cpp:371
#22 0x010f3a7e in qt_x11EventFilter (ev=0xbfa9576c) at /usr/src/kde4/src/qt-copy/src/gui/kernel/qapplication_x11.cpp:367
#23 0x01101d65 in QApplication::x11ProcessEvent (this=0x80d77f8, event=0xbfa9576c) at /usr/src/kde4/src/qt-copy/src/gui/kernel/qapplication_x11.cpp:2992
#24 0x0112949b in x11EventSourceDispatch (s=0x80f8028, callback=0, user_data=0x0) at /usr/src/kde4/src/qt-copy/src/gui/kernel/qguieventdispatcher_glib.cpp:148
#25 0x072eae38 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#26 0x072ee4e3 in ?? () from /lib/libglib-2.0.so.0
#27 0x072ee6a1 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#28 0x053423fe in QEventDispatcherGlib::processEvents (this=0x80d8310, flags=@0xbfa95978) at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qeventdispatcher_glib.cpp:325
#29 0x01129285 in QGuiEventDispatcherGlib::processEvents (this=0x80d8310, flags=@0xbfa959a8) at /usr/src/kde4/src/qt-copy/src/gui/kernel/qguieventdispatcher_glib.cpp:204
#30 0x0531613d in QEventLoop::processEvents (this=0xbfa95a20, flags=@0xbfa959e8) at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qeventloop.cpp:149
#31 0x053162cd in QEventLoop::exec (this=0xbfa95a20, flags=@0xbfa95a28) at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qeventloop.cpp:200
#32 0x0531829d in QCoreApplication::exec () at /usr/src/kde4/src/qt-copy/src/corelib/kernel/qcoreapplication.cpp:845
#33 0x01098627 in QApplication::exec () at /usr/src/kde4/src/qt-copy/src/gui/kernel/qapplication.cpp:3298
#34 0x0013c401 in kdemain (argc=1, argv=0xbfa95bf4) at /home/trever/Projects/kde/kdebase/workspace/plasma/shells/desktop/main.cpp:58
#35 0x08048712 in main (argc=142256416, argv=0x87ca5d0) at /home/trever/Projects/kde/build/kdebase/workspace/plasma/shells/desktop/plasma_qgv_dummy.cpp:3