I just surfed the web while plasma crashed. DrKonqi wasn't able to find the right debug symbols and I installed it by hand. But even after that it wasn't able to use them.
KDE and debug symbols installed from ppa:kubuntu-ppa/backports.

Application: Оболонка стільниці Плазми (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fc2dae23780 (LWP 2355))]

Thread 4 (Thread 0x7fc2b9986700 (LWP 2356)):
#0  0x00007fc2ce9fe05d in __pthread_mutex_unlock_usercnt (mutex=<optimized out>, decr=<optimized out>) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=0x7fc2b4000a60) at pthread_mutex_unlock.c:290
#2  0x00007fc2ce338e51 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fc2ce2fb9a9 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fc2ce2fbde8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fc2ce2fbea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007fc2d72f5c46 in QEventDispatcherGlib::processEvents (this=0x7fc2b40008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#7  0x00007fc2d72c62ef in QEventLoop::processEvents (this=this@entry=0x7fc2b9985dd0, flags=...) at kernel/qeventloop.cpp:149
#8  0x00007fc2d72c6578 in QEventLoop::exec (this=0x7fc2b9985dd0, flags=...) at kernel/qeventloop.cpp:204
#9  0x00007fc2d71c7b40 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#10 0x00007fc2d72a69df in QInotifyFileSystemWatcherEngine::run (this=0xedb930) at io/qfilesystemwatcher_inotify.cpp:248
#11 0x00007fc2d71cab1c in QThreadPrivate::start (arg=0xedb930) at thread/qthread_unix.cpp:338
#12 0x00007fc2ce9fae9a in start_thread (arg=0x7fc2b9986700) at pthread_create.c:308
#13 0x00007fc2da708cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#14 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7fc2b27de700 (LWP 2357)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007fc2d434ccd7 in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7fc2d465a660 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007fc2d434cd09 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007fc2ce9fae9a in start_thread (arg=0x7fc2b27de700) at pthread_create.c:308
#4  0x00007fc2da708cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fc2ab041700 (LWP 2364)):
#0  0x00007fc2ce2f990c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007fc2ce2fb597 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fc2ce2fbcab in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fc2ce2fbea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fc2d72f5c46 in QEventDispatcherGlib::processEvents (this=0x7fc29c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#5  0x00007fc2d72c62ef in QEventLoop::processEvents (this=this@entry=0x7fc2ab040dd0, flags=...) at kernel/qeventloop.cpp:149
#6  0x00007fc2d72c6578 in QEventLoop::exec (this=0x7fc2ab040dd0, flags=...) at kernel/qeventloop.cpp:204
#7  0x00007fc2d71c7b40 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#8  0x00007fc2d72a69df in QInotifyFileSystemWatcherEngine::run (this=0x19d9670) at io/qfilesystemwatcher_inotify.cpp:248
#9  0x00007fc2d71cab1c in QThreadPrivate::start (arg=0x19d9670) at thread/qthread_unix.cpp:338
#10 0x00007fc2ce9fae9a in start_thread (arg=0x7fc2ab041700) at pthread_create.c:308
#11 0x00007fc2da708cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fc2dae23780 (LWP 2355)):
[KCrash Handler]
#6  0x00007fc2d72dbc6e in QMetaObject::addGuard (ptr=0x7fff9f19c2c0) at kernel/qobject.cpp:401
#7  0x00007fc2d8ed7e0e in QPointer (p=..., this=0x7fff9f19c2c0) at ../../include/QtCore/../../src/corelib/kernel/qpointer.h:62
#8  takeAt (i=5, this=0x2c10e58) at ../../include/QtCore/../../src/corelib/tools/qlist.h:486
#9  QDeclarativeRepeater::itemsRemoved (this=0x2c10ba0, index=5, count=<optimized out>) at graphicsitems/qdeclarativerepeater.cpp:407
#10 0x00007fc2d72dcf8f in QMetaObject::activate (sender=0x2c11410, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff9f19c440) at kernel/qobject.cpp:3547
#11 0x00007fc2d901ce6f in QDeclarativeVisualModel::itemsRemoved (this=<optimized out>, _t1=5, _t2=1) at .moc/release-shared/moc_qdeclarativevisualitemmodel_p.cpp:161
#12 0x00007fc2d8eeed6c in QDeclarativeVisualDataModel::_q_itemsRemoved (this=0x2c11410, index=5, count=1) at graphicsitems/qdeclarativevisualitemmodel.cpp:1314
#13 0x00007fc2d901d4a1 in QDeclarativeVisualDataModel::qt_static_metacall (_o=0x7fff9f19c2c0, _c=QMetaObject::QueryPropertyScriptable, _id=10007824, _a=0x1) at .moc/release-shared/moc_qdeclarativevisualitemmodel_p.cpp:401
#14 0x00007fc2d72dcf8f in QMetaObject::activate (sender=0x243cb60, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff9f19c680) at kernel/qobject.cpp:3547
#15 0x00007fc2d90118ff in QListModelInterface::itemsRemoved (this=<optimized out>, _t1=5, _t2=1) at .moc/release-shared/moc_qlistmodelinterface_p.cpp:114
#16 0x00007fc2d8e5a37f in QDeclarativeListModel::remove (this=0x243cb60, index=5) at util/qdeclarativelistmodel.cpp:402
#17 0x00007fc2d90104cb in QDeclarativeListModel::qt_static_metacall (_o=0x7fff9f19c2c0, _o@entry=0x243cb60, _c=QMetaObject::QueryPropertyScriptable, _c@entry=QMetaObject::InvokeMetaMethod, _id=10007824, _id@entry=2, _a=0x1, _a@entry=0x7fff9f19c910) at .moc/release-shared/moc_qdeclarativelistmodel_p.cpp:76
#18 0x00007fc2d90105cf in QDeclarativeListModel::qt_metacall (this=0x243cb60, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7fff9f19c910) at .moc/release-shared/moc_qdeclarativelistmodel_p.cpp:123
#19 0x00007fc2d8fbb018 in QDeclarativeObjectMethodScriptClass::callMethod (this=this@entry=0x1e9a4d0, object=object@entry=0x243cb60, index=10, returnType=<optimized out>, argCount=<optimized out>, argTypes=0x7fff9f19cbd0, ctxt=ctxt@entry=0x7fc2a9dc02a8) at qml/qdeclarativeobjectscriptclass.cpp:970
#20 0x00007fc2d8fbcc86 in QDeclarativeObjectMethodScriptClass::callPrecise (this=0x1e9a4d0, object=0x243cb60, data=..., ctxt=0x7fc2a9dc02a8) at qml/qdeclarativeobjectscriptclass.cpp:944
#21 0x00007fc2d8fbd5bb in QDeclarativeObjectMethodScriptClass::call (this=<optimized out>, o=<optimized out>, ctxt=<optimized out>) at qml/qdeclarativeobjectscriptclass.cpp:917
#22 0x00007fc2d43c30b3 in QScript::DeclarativeObjectDelegate::call (exec=<optimized out>, callee=0x7fc2aded3dc0, thisValue=..., args=...) at bridge/qscriptdeclarativeobject.cpp:154
#23 0x00007fc2d42bf1d0 in QTJSC::NativeFuncWrapper::operator() (this=0x7fff9f19cd20, exec=0x7fc2a9dc02a8, jsobj=0x7fc2aded3dc0, thisValue=..., argList=...) at ../3rdparty/javascriptcore/JavaScriptCore/runtime/CallData.cpp:46
#24 0x00007fc2d429c2c6 in QTJSC::cti_op_call_NotJSFunction (args=0x7fff9f19cd70) at ../3rdparty/javascriptcore/JavaScriptCore/jit/JITStubs.cpp:1780
#25 0x00007fc2ac0f71b8 in ?? ()
#26 0x7fffffff00000001 in ?? ()
#27 0x00007fc2aded3dc0 in ?? ()
#28 0x00007fc20000000b in ?? ()
#29 0x0000000000000002 in ?? ()
#30 0x00007fc2a92759a0 in ?? ()
#31 0x00007fc2a830cde0 in ?? ()
#32 0x00007fc2ac9615d8 in ?? ()
#33 0x00007fc2a8342000 in ?? ()
#34 0x00007fc2a9342180 in ?? ()
#35 0x00007fc2ac0f6f80 in ?? ()
#36 0x00007fc2ac9615f0 in ?? ()
#37 0x00007fc2a9dc02a8 in ?? ()
#38 0x00007fc2b8121288 in ?? ()
#39 0x00007fc2d4645d98 in QTJSC::ExecutableAllocator::pageSize () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#40 0x00007fc2b8120000 in ?? ()
#41 0x00007fc2a9dc0208 in ?? ()
#42 0x00007fc2a927f070 in ?? ()
#43 0x00007fc2d4645d98 in QTJSC::ExecutableAllocator::pageSize () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#44 0x00007fc2a9dc0208 in ?? ()
#45 0x00007fc2a9dc0250 in ?? ()
#46 0x00007fc2ac9615d8 in ?? ()
#47 0x00007fc2d425a8d9 in execute (exception=0x7fc2b8121288, globalData=0x7fc2b8120000, callFrame=0x200, registerFile=0x7fff9f19ce28, this=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/jit/JITCode.h:79
#48 QTJSC::Interpreter::execute (this=0x7fff9f19ce10, functionExecutable=0xffff000000000002, callFrame=0x7fc2a9dc0250, function=0x7fc2aded3d00, thisObj=<optimized out>, args=..., scopeChain=0x7fc2a830cde0, exception=0x7fc2b8121288) at ../3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.cpp:716
#49 0x00007fc2d42eb817 in QTJSC::JSFunction::call (this=0x7fc2aded3d00, exec=0x7fc2a9dc0208, thisValue=..., args=...) at ../3rdparty/javascriptcore/JavaScriptCore/runtime/JSFunction.cpp:122
#50 0x00007fc2d42bf1ff in QTJSC::call (exec=<optimized out>, functionObject=..., callType=<optimized out>, callData=..., thisValue=..., args=...) at ../3rdparty/javascriptcore/JavaScriptCore/runtime/CallData.cpp:62
#51 0x00007fc2d43a699e in QScriptValue::call (this=<optimized out>, thisObject=..., args=...) at api/qscriptvalue.cpp:1604
#52 0x00007fc2d8f27f35 in QDeclarativeQtScriptExpression::eval (this=this@entry=0x36f20b8, secondaryScope=<optimized out>, isUndefined=0x0) at qml/qdeclarativeexpression.cpp:518
#53 0x00007fc2d8f282b1 in QDeclarativeQtScriptExpression::scriptValue (this=this@entry=0x36f20b8, secondaryScope=secondaryScope@entry=0x0, isUndefined=isUndefined@entry=0x0) at qml/qdeclarativeexpression.cpp:470
#54 0x00007fc2d8f285be in QDeclarativeExpressionPrivate::scriptValue (this=this@entry=0x36f2030, secondaryScope=secondaryScope@entry=0x0, isUndefined=isUndefined@entry=0x0) at qml/qdeclarativeexpression.cpp:653
#55 0x00007fc2d8f28752 in QDeclarativeExpressionPrivate::value (this=0x36f2030, secondaryScope=0x0, isUndefined=0x0) at qml/qdeclarativeexpression.cpp:667
#56 0x00007fc2d8f5fd33 in QDeclarativeBoundSignal::qt_metacall (this=0x4080270, c=<optimized out>, id=<optimized out>, a=0x7fff9f19d370) at qml/qdeclarativeboundsignal.cpp:196
#57 0x00007fc2d72dd153 in QMetaObject::activate (sender=0x3673e90, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3566
#58 0x00007fc2d8e641ad in QDeclarativeTimer::finished (this=0x3673e90) at util/qdeclarativetimer.cpp:318
#59 0x00007fc2d72dcf8f in QMetaObject::activate (sender=0x3bd3660, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3547
#60 0x00007fc2d71aeb88 in QAbstractAnimationPrivate::setState (this=0x3b089e0, newState=newState@entry=QAbstractAnimation::Stopped) at animation/qabstractanimation.cpp:604
#61 0x00007fc2d71aec97 in QAbstractAnimation::stop (this=this@entry=0x3bd3660) at animation/qabstractanimation.cpp:958
#62 0x00007fc2d71aede3 in QAbstractAnimation::setCurrentTime (this=this@entry=0x3bd3660, msecs=<optimized out>) at animation/qabstractanimation.cpp:912
#63 0x00007fc2d71aefa4 in updateAnimationsTime (this=0x9d56a0) at animation/qabstractanimation.cpp:235
#64 QUnifiedTimer::updateAnimationsTime (this=0x9d56a0) at animation/qabstractanimation.cpp:207
#65 0x00007fc2d71aea9a in QAbstractAnimationPrivate::setState (this=0x3b53c60, newState=QAbstractAnimation::Running) at animation/qabstractanimation.cpp:588
#66 0x00007fc2d8e63e48 in QDeclarativeTimer::update (this=0x3f52c40) at util/qdeclarativetimer.cpp:279
#67 0x00007fc2d8f32663 in QDeclarativeComponentPrivate::complete (enginePriv=0x1ead050, state=0x2c112f8) at qml/qdeclarativecomponent.cpp:962
#68 0x00007fc2d8f32c9b in completeCreate (this=<optimized out>) at qml/qdeclarativecomponent.cpp:1043
#69 QDeclarativeComponentPrivate::completeCreate (this=<optimized out>) at qml/qdeclarativecomponent.cpp:1039
#70 0x00007fc2d8eef928 in QDeclarativeVisualDataModel::item (this=0x2c11410, index=0, viewId=..., complete=complete@entry=true) at graphicsitems/qdeclarativevisualitemmodel.cpp:1069
#71 0x00007fc2d8eefecb in QDeclarativeVisualDataModel::item (this=<optimized out>, index=0, complete=<optimized out>) at graphicsitems/qdeclarativevisualitemmodel.cpp:958
#72 0x00007fc2d8ed7c04 in QDeclarativeRepeater::itemsInserted (this=0x2c10ba0, index=<optimized out>, count=<optimized out>) at graphicsitems/qdeclarativerepeater.cpp:386
#73 0x00007fc2d72dcf8f in QMetaObject::activate (sender=0x2c11410, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff9f19db20) at kernel/qobject.cpp:3547
#74 0x00007fc2d901ce1f in QDeclarativeVisualModel::itemsInserted (this=<optimized out>, _t1=0, _t2=1) at .moc/release-shared/moc_qdeclarativevisualitemmodel_p.cpp:154
#75 0x00007fc2d8eee80c in QDeclarativeVisualDataModel::_q_itemsInserted (this=0x2c11410, index=0, count=1) at graphicsitems/qdeclarativevisualitemmodel.cpp:1282
#76 0x00007fc2d901d481 in QDeclarativeVisualDataModel::qt_static_metacall (_o=0x7fff9f19c2c0, _c=QMetaObject::QueryPropertyScriptable, _id=10007824, _a=0x1) at .moc/release-shared/moc_qdeclarativevisualitemmodel_p.cpp:400
#77 0x00007fc2d72dcf8f in QMetaObject::activate (sender=0x243cb60, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff9f19dd50) at kernel/qobject.cpp:3547
#78 0x00007fc2d90118ac in QListModelInterface::itemsInserted (this=<optimized out>, _t1=0, _t2=1) at .moc/release-shared/moc_qlistmodelinterface_p.cpp:107
#79 0x00007fc2d8e58ffb in QDeclarativeListModel::insert (this=0x243cb60, index=0, valuemap=...) at util/qdeclarativelistmodel.cpp:436
#80 0x00007fc2d901049f in QDeclarativeListModel::qt_static_metacall (_o=0x7fff9f19c2c0, _o@entry=0x243cb60, _c=QMetaObject::QueryPropertyScriptable, _c@entry=QMetaObject::InvokeMetaMethod, _id=10007824, _id@entry=4, _a=0x1, _a@entry=0x7fff9f19dff0) at .moc/release-shared/moc_qdeclarativelistmodel_p.cpp:78
#81 0x00007fc2d90105cf in QDeclarativeListModel::qt_metacall (this=0x243cb60, _c=QMetaObject::InvokeMetaMethod, _id=4, _a=0x7fff9f19dff0) at .moc/release-shared/moc_qdeclarativelistmodel_p.cpp:123
#82 0x00007fc2d8fbb018 in QDeclarativeObjectMethodScriptClass::callMethod (this=this@entry=0x1e9a4d0, object=object@entry=0x243cb60, index=12, returnType=<optimized out>, argCount=<optimized out>, argTypes=0x7fff9f19e2b0, ctxt=ctxt@entry=0x7fc2a9dc0208) at qml/qdeclarativeobjectscriptclass.cpp:970
#83 0x00007fc2d8fbcc86 in QDeclarativeObjectMethodScriptClass::callPrecise (this=0x1e9a4d0, object=0x243cb60, data=..., ctxt=0x7fc2a9dc0208) at qml/qdeclarativeobjectscriptclass.cpp:944
#84 0x00007fc2d8fbd5bb in QDeclarativeObjectMethodScriptClass::call (this=<optimized out>, o=<optimized out>, ctxt=<optimized out>) at qml/qdeclarativeobjectscriptclass.cpp:917
#85 0x00007fc2d43c30b3 in QScript::DeclarativeObjectDelegate::call (exec=<optimized out>, callee=0x7fc2adecda00, thisValue=..., args=...) at bridge/qscriptdeclarativeobject.cpp:154
#86 0x00007fc2d42bf1d0 in QTJSC::NativeFuncWrapper::operator() (this=0x7fff9f19e400, exec=0x7fc2a9dc0208, jsobj=0x7fc2adecda00, thisValue=..., argList=...) at ../3rdparty/javascriptcore/JavaScriptCore/runtime/CallData.cpp:46
#87 0x00007fc2d429c2c6 in QTJSC::cti_op_call_NotJSFunction (args=0x7fff9f19e450) at ../3rdparty/javascriptcore/JavaScriptCore/jit/JITStubs.cpp:1780
#88 0x00007fc2b060940b in ?? ()
#89 0x0000000000000000 in ?? ()

Reproducible: Didn't try