Opened System Settings then clicked on Workspace Theme.

I'm using Project Neon 5 development ppas:
(system settings - 0.0+git20141001.0314+neon4~a4f9aa9~14.04)


Reproducible: Always

Steps to Reproduce:
1. Open System Settings
2. Click on Workspace Theme

Actual Results:  
The crash can be reproduced every time.


-- Backtrace:
Application: System Settings (systemsettings5), signal: Aborted
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0xb3606700 (LWP 3892))]

Thread 3 (Thread 0xb3168b40 (LWP 3893)):
#0  0xb77a2424 in __kernel_vsyscall ()
#1  0xb5d1f56b in poll () at ../sysdeps/unix/syscall-template.S:81
#2  0xb58c43a8 in ?? () from /usr/lib/i386-linux-gnu/libxcb.so.1
#3  0xb58c6394 in xcb_wait_for_event () from /usr/lib/i386-linux-gnu/libxcb.so.1
#4  0xb330d39a in QXcbEventReader::run (this=0x863a968) at qxcbconnection.cpp:1046
#5  0xb5f9079b in QThreadPrivate::start (arg=0x863a968) at thread/qthread_unix.cpp:345
#6  0xb54eef70 in start_thread (arg=0xb3168b40) at pthread_create.c:312
#7  0xb5d2e4ce in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:129

Thread 2 (Thread 0xaeffcb40 (LWP 3895)):
#0  0xb54f21f9 in __GI___pthread_mutex_unlock (mutex=0xae600550) at pthread_mutex_unlock.c:310
#1  0xb5d3b8f4 in pthread_mutex_unlock (mutex=0xae600550) at forward.c:194
#2  0xb5416140 in g_mutex_unlock () from /lib/i386-linux-gnu/libglib-2.0.so.0
#3  0xb53d0515 in g_main_context_release () from /lib/i386-linux-gnu/libglib-2.0.so.0
#4  0xb53d1390 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#5  0xb53d1528 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#6  0xb6204c24 in QEventDispatcherGlib::processEvents (this=0xae600468, flags=...) at kernel/qeventdispatcher_glib.cpp:428
#7  0xb61944e3 in QEventLoop::processEvents (this=0xaeffc2d8, flags=...) at kernel/qeventloop.cpp:136
#8  0xb61947aa in QEventLoop::exec (this=0xaeffc2d8, flags=...) at kernel/qeventloop.cpp:212
#9  0xb5f89bd5 in QThread::exec (this=0x8848880) at thread/qthread.cpp:511
#10 0xaf7f79ee in QQmlThreadPrivate::run (this=0x8848880) at qml/ftw/qqmlthread.cpp:149
#11 0xb5f9079b in QThreadPrivate::start (arg=0x8848880) at thread/qthread_unix.cpp:345
#12 0xb54eef70 in start_thread (arg=0xaeffcb40) at pthread_create.c:312
#13 0xb5d2e4ce in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:129

Thread 1 (Thread 0xb3606700 (LWP 3892)):
[KCrash Handler]
#7  0xb77a2424 in __kernel_vsyscall ()
#8  0xb5c70577 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#9  0xb5c739a3 in __GI_abort () at abort.c:89
#10 0xb5f7ed5a in qt_message_fatal (context=..., message=...) at global/qlogging.cpp:1364
#11 0xb5f7c907 in QMessageLogger::fatal (this=0xbfe038cc, msg=0xb768df18 "Accessed invalid KPluginInfo object") at global/qlogging.cpp:669
#12 0xb76706fb in KPluginInfo::name (this=0xbfe0393c) at /build/buildd/project-neon5-kservice-0.0+git20141001.0308+neon4~d1fc280~14.04/src/services/kplugininfo.cpp:308
#13 0xafb31542 in KCMLookandFeel::load (this=0x883a2b8) at /build/buildd/project-neon5-plasma-desktop-0.0+git20141001.0313+neon4~f02df03~14.04/kcms/lookandfeel/kcm.cpp:176
#14 0xafb460ae in KCMLookandFeel::qt_static_metacall (_o=0x883a2b8, _c=QMetaObject::InvokeMetaMethod, _id=5, _a=0x8843278) at /build/buildd/project-neon5-plasma-desktop-0.0+git20141001.0313+neon4~f02df03~14.04/obj-i686-linux-gnu/kcms/lookandfeel/moc_kcm.cpp:126
#15 0xb61cd216 in QMetaCallEvent::placeMetaCall (this=0x883a0b8, object=0x883a2b8) at kernel/qobject.cpp:487
#16 0xb61ce053 in QObject::event (this=0x883a2b8, e=0x883a0b8) at kernel/qobject.cpp:1241
#17 0xb6ccda35 in QWidget::event (this=0x883a2b8, event=0x883a0b8) at kernel/qwidget.cpp:8371
#18 0xb6c86e1e in QApplicationPrivate::notify_helper (this=0x862a298, receiver=0x883a2b8, e=0x883a0b8) at kernel/qapplication.cpp:3499
#19 0xb6c86c98 in QApplication::notify (this=0xbfe041d4, receiver=0x883a2b8, e=0x883a0b8) at kernel/qapplication.cpp:3464
#20 0xb6197651 in QCoreApplication::notifyInternal (this=0xbfe041d4, receiver=0x883a2b8, event=0x883a0b8) at kernel/qcoreapplication.cpp:935
#21 0xb619b045 in QCoreApplication::sendEvent (receiver=0x883a2b8, event=0x883a0b8) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:237
#22 0xb61987ba in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x8629e88) at kernel/qcoreapplication.cpp:1539
#23 0xb619827e in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1397
#24 0xb6204542 in postEventSourceDispatch (s=0x865c3f8) at kernel/qeventdispatcher_glib.cpp:279
#25 0xb53d11e3 in g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0
#26 0xb53d1468 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#27 0xb53d1528 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#28 0xb6204c04 in QEventDispatcherGlib::processEvents (this=0x8660620, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#29 0xb3362aa6 in QPAEventDispatcherGlib::processEvents (this=0x8660620, flags=...) at eventdispatchers/qeventdispatcher_glib.cpp:123
#30 0xb61944e3 in QEventLoop::processEvents (this=0xbfe0411c, flags=...) at kernel/qeventloop.cpp:136
#31 0xb61947aa in QEventLoop::exec (this=0xbfe0411c, flags=...) at kernel/qeventloop.cpp:212
#32 0xb6197d31 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#33 0xb66b5ddc in QGuiApplication::exec () at kernel/qguiapplication.cpp:1483
#34 0xb6c83db3 in QApplication::exec () at kernel/qapplication.cpp:2744
#35 0x0806554e in main (argc=1, argv=0xbfe042a4) at /build/buildd/project-neon5-systemsettings-0.0+git20141001.0314+neon4~a4f9aa9~14.04/app/main.cpp:55