After an interrupted restart (power killed while computer was shutting down), plasma desktop shell crashes immediately after login. 

backtrace:
Application: Plasma Desktop Shell (plasma-desktop), signal: Bus error
[Current thread is 1 (Thread 0x7f30d3bfa7a0 (LWP 1829))]

Thread 3 (Thread 0x7f30ab825700 (LWP 1876)):
#0  0x00007f30c7820fba in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f30c7821dfd in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f30c7822429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f30d06c9f3e in QEventDispatcherGlib::processEvents (this=0x382f390, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#4  0x00007f30d069dcf2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f30d069def7 in QEventLoop::exec (this=0x7f30ab824db0, flags=...) at kernel/qeventloop.cpp:201
#6  0x00007f30d05b527f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:498
#7  0x00007f30d0680cbf in QInotifyFileSystemWatcherEngine::run (this=0x382edb0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f30d05b7d05 in QThreadPrivate::start (arg=0x382edb0) at thread/qthread_unix.cpp:331
#9  0x00007f30c832eefc in start_thread (arg=0x7f30ab825700) at pthread_create.c:304
#10 0x00007f30d34eb59d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f30a9493700 (LWP 1877)):
#0  0xffffffffff60017b in ?? ()
#1  0x00007f30a9492ad0 in ?? ()
#2  0x00007fff1d3ff7e7 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 1 (Thread 0x7f30d3bfa7a0 (LWP 1829)):
[KCrash Handler]
#6  __strncmp_ssse3 () at ../sysdeps/x86_64/multiarch/../strcmp.S:1237
#7  0x00007f30d0e81c31 in qstrncmp (len=<optimized out>, str2=<optimized out>, str1=<optimized out>) at /usr/include/qt4/QtCore/qbytearray.h:92
#8  findNamedEntry (key=..., this=0x7f30ad320000) at ../../kdecore/util/kshareddatacache.cpp:710
#9  KSharedDataCache::find (this=<optimized out>, key=<optimized out>, destination=0x7fff1d3dc410) at ../../kdecore/util/kshareddatacache.cpp:1499
#10 0x00007f30d13b3a5f in KImageCache::findPixmap (this=0x3718890, key=..., destination=0x7fff1d3dc480) at ../../kdeui/util/kimagecache.cpp:150
#11 0x00007f30d30a9cea in Plasma::Theme::findInCache (this=0x26a7fd0, key=..., pix=...) at ../../plasma/theme.cpp:924
#12 0x00007f30d30a6e9f in Plasma::SvgPrivate::findInCache (this=0x4130370, elementId=..., s=<optimized out>) at ../../plasma/svg.cpp:339
#13 0x00007f30d30a7354 in Plasma::Svg::paint (this=<optimized out>, painter=0x7fff1d3dce90, rect=..., elementID=<optimized out>) at ../../plasma/svg.cpp:674
#14 0x00007f30d30380a4 in Plasma::FrameSvgPrivate::generateFrameBackground (this=0x41303f0, frame=0x40b56f0) at ../../plasma/framesvg.cpp:800
#15 0x00007f30d3038e33 in Plasma::FrameSvgPrivate::generateBackground (this=0x41303f0, frame=0x40b56f0) at ../../plasma/framesvg.cpp:679
#16 0x00007f30d303a0d9 in Plasma::FrameSvgPrivate::generateBackground (this=0x41303f0, frame=0x40b56f0) at ../../plasma/framesvg.cpp:659
#17 0x00007f30d303a468 in Plasma::FrameSvg::framePixmap (this=0x412edf0) at ../../plasma/framesvg.cpp:503
#18 0x00007f30d304d72b in Plasma::FocusIndicator::resizeEvent (this=0x40b0d80) at ../../plasma/private/focusindicator.cpp:247
#19 0x00007f30d006ca17 in QGraphicsWidget::event (this=0x40b0d80, event=0x7fff1d3dda50) at graphicsview/qgraphicswidget.cpp:1387
#20 0x00007f30cfa4e474 in notify_helper (e=0x7fff1d3dda50, receiver=0x40b0d80, this=0x260fd30) at kernel/qapplication.cpp:4486
#21 QApplicationPrivate::notify_helper (this=0x260fd30, receiver=0x40b0d80, e=0x7fff1d3dda50) at kernel/qapplication.cpp:4458
#22 0x00007f30cfa532e1 in QApplication::notify (this=0x2608bd0, receiver=0x40b0d80, e=0x7fff1d3dda50) at kernel/qapplication.cpp:4365
#23 0x00007f30d134d466 in KApplication::notify (this=0x2608bd0, receiver=0x40b0d80, event=0x7fff1d3dda50) at ../../kdeui/kernel/kapplication.cpp:311
#24 0x00007f30d069eafc in QCoreApplication::notifyInternal (this=0x2608bd0, receiver=0x40b0d80, event=0x7fff1d3dda50) at kernel/qcoreapplication.cpp:787
#25 0x00007f30d006df23 in sendEvent (event=0x7fff1d3dda50, receiver=0x40b0d80) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#26 QGraphicsWidget::setGeometry (this=0x40b0d80, rect=<optimized out>) at graphicsview/qgraphicswidget.cpp:407
#27 0x00007f30d304e377 in syncGeometry (this=0x40b0d80) at ../../plasma/private/focusindicator.cpp:299
#28 Plasma::FocusIndicator::syncGeometry (this=0x40b0d80) at ../../plasma/private/focusindicator.cpp:277
#29 0x00007f30d304f0ed in Plasma::FocusIndicator::eventFilter (this=0x40b0d80, event=<optimized out>, watched=<optimized out>) at ../../plasma/private/focusindicator.cpp:176
#30 0x00007f30d3050110 in Plasma::FocusIndicator::eventFilter (this=0x40b0d80, watched=0x412ccb0, event=0x7fff1d3de470) at ../../plasma/private/focusindicator.cpp:125
#31 0x00007f30d069ec88 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0x412ccb0, event=0x7fff1d3de470) at kernel/qcoreapplication.cpp:902
#32 0x00007f30cfa4e43f in notify_helper (e=0x7fff1d3de470, receiver=0x412ccb0, this=0x260fd30) at kernel/qapplication.cpp:4482
#33 QApplicationPrivate::notify_helper (this=0x260fd30, receiver=0x412ccb0, e=0x7fff1d3de470) at kernel/qapplication.cpp:4458
#34 0x00007f30cfa532e1 in QApplication::notify (this=0x2608bd0, receiver=0x412ccb0, e=0x7fff1d3de470) at kernel/qapplication.cpp:4365
#35 0x00007f30d134d466 in KApplication::notify (this=0x2608bd0, receiver=0x412ccb0, event=0x7fff1d3de470) at ../../kdeui/kernel/kapplication.cpp:311
#36 0x00007f30d069eafc in QCoreApplication::notifyInternal (this=0x2608bd0, receiver=0x412ccb0, event=0x7fff1d3de470) at kernel/qcoreapplication.cpp:787
#37 0x00007f30d006df23 in sendEvent (event=0x7fff1d3de470, receiver=0x412ccb0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#38 QGraphicsWidget::setGeometry (this=0x412ccb0, rect=<optimized out>) at graphicsview/qgraphicswidget.cpp:407
#39 0x00007f30d006bb68 in QGraphicsWidget::resize (this=0x412ccb0, size=...) at graphicsview/qgraphicswidget.cpp:309
#40 0x00007f30d006e58b in QGraphicsWidget::updateGeometry (this=0x412ccb0) at graphicsview/qgraphicswidget.cpp:1094
#41 0x00007f30d00352ed in QGraphicsProxyWidgetPrivate::setWidget_helper (this=0x412f870, newWidget=0x4130e10, autoShow=true) at graphicsview/qgraphicsproxywidget.cpp:709
#42 0x00007f30d30bfdbd in Plasma::ComboBox::setNativeWidget (this=0x412ccb0, nativeWidget=0x4130e10) at ../../plasma/widgets/combobox.cpp:169
#43 0x00007f30d30c0133 in Plasma::ComboBox::ComboBox (this=0x412ccb0, parent=<optimized out>) at ../../plasma/widgets/combobox.cpp:131
#44 0x00007f30a0cad7ca in ?? () from /usr/lib/kde4/plasma_applet_battery.so
#45 0x00007f30a0cb26c8 in ?? () from /usr/lib/kde4/plasma_applet_battery.so
#46 0x00007f30b979979d in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#47 0x00007f30b9790bc1 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#48 0x00007f30b97ac206 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#49 0x00007f30b97ac926 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#50 0x00007f30b97ad124 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#51 0x00007f30d06b1eba in QMetaObject::activate (sender=0x2846d00, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff1d3df240) at kernel/qobject.cpp:3278
#52 0x00007f30b978f87f in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#53 0x00007f30b978fa95 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#54 0x00007f30b978fbe4 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#55 0x00007f30d06b1eba in QMetaObject::activate (sender=0x2843780, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff1d3df3b0) at kernel/qobject.cpp:3278
#56 0x00007f30b979008f in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#57 0x00007f30b9797178 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#58 0x00007f30b97983ef in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#59 0x00007f30b97a3595 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#60 0x00007f30b97a1281 in ?? () from /usr/lib/kde4/plasma_applet_systemtray.so
#61 0x00007f30d2fe60bf in Plasma::Applet::flushPendingConstraintsEvents (this=0x2843e10) at ../../plasma/applet.cpp:1365
#62 0x00007f30d2ff63f7 in Plasma::ContainmentPrivate::initApplets (this=0x27ed740) at ../../plasma/containment.cpp:470
#63 0x00007f30d300ab52 in Plasma::CoronaPrivate::importLayout (this=0x2739830, conf=<optimized out>, mergeConfig=false) at ../../plasma/corona.cpp:1066
#64 0x00007f30d300b824 in Plasma::Corona::loadLayout (this=0x273a180, configName=...) at ../../plasma/corona.cpp:278
#65 0x00007f30d300b8ec in Plasma::Corona::initializeLayout (this=0x273a180, configName=...) at ../../plasma/corona.cpp:181
#66 0x00007f30d380344b in ?? () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#67 0x00007f30d380376a in ?? () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#68 0x00007f30d3804f42 in ?? () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#69 0x00007f30d06b5a5e in QObject::event (this=0x2608bd0, e=<optimized out>) at kernel/qobject.cpp:1217
#70 0x00007f30cfa52324 in QApplication::event (this=0x2608bd0, e=0x270e410) at kernel/qapplication.cpp:2527
#71 0x00007f30cfa4e474 in notify_helper (e=0x270e410, receiver=0x2608bd0, this=0x260fd30) at kernel/qapplication.cpp:4486
#72 QApplicationPrivate::notify_helper (this=0x260fd30, receiver=0x2608bd0, e=0x270e410) at kernel/qapplication.cpp:4458
#73 0x00007f30cfa532e1 in QApplication::notify (this=0x2608bd0, receiver=0x2608bd0, e=0x270e410) at kernel/qapplication.cpp:4365
#74 0x00007f30d134d466 in KApplication::notify (this=0x2608bd0, receiver=0x2608bd0, event=0x270e410) at ../../kdeui/kernel/kapplication.cpp:311
#75 0x00007f30d069eafc in QCoreApplication::notifyInternal (this=0x2608bd0, receiver=0x2608bd0, event=0x270e410) at kernel/qcoreapplication.cpp:787
#76 0x00007f30d06a251f in sendEvent (event=0x270e410, receiver=0x2608bd0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#77 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x259b430) at kernel/qcoreapplication.cpp:1428
#78 0x00007f30d06c9a73 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#79 postEventSourceDispatch (s=<optimized out>) at kernel/qeventdispatcher_glib.cpp:277
#80 0x00007f30c7821a5d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#81 0x00007f30c7822258 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#82 0x00007f30c7822429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#83 0x00007f30d06c9ed6 in QEventDispatcherGlib::processEvents (this=0x259cf40, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:422
#84 0x00007f30cfaf610e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=<optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#85 0x00007f30d069dcf2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#86 0x00007f30d069def7 in QEventLoop::exec (this=0x7fff1d3e09f0, flags=...) at kernel/qeventloop.cpp:201
#87 0x00007f30d06a2789 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1064
#88 0x00007f30d37ea1a3 in kdemain () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#89 0x00007f30d342930d in __libc_start_main (main=0x400640, argc=1, ubp_av=0x7fff1d3e0dd8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff1d3e0dc8) at libc-start.c:226
#90 0x0000000000400671 in _start ()