Comment 4 for bug 1465866

I can confirm this on Kubuntu 15.10. I run
sudo gdb -p <pid-of-ksmserver>
(gdb) backtrace

and this is the output:
(gdb) backtrace
#0 0x00007f5524e41e15 in _nv014tls () from /usr/lib/nvidia-352/tls/libnvidia-tls.so.352.41
#1 0x00007f55274c85cd in ?? () from /usr/lib/nvidia-352/libGL.so.1
#2 0x00007f55274c8998 in ?? () from /usr/lib/nvidia-352/libGL.so.1
#3 0x00007f552746d6f2 in ?? () from /usr/lib/nvidia-352/libGL.so.1
#4 0x00007f552749a51e in ?? () from /usr/lib/nvidia-352/libGL.so.1
#5 0x00007f552749edd8 in ?? () from /usr/lib/nvidia-352/libGL.so.1
#6 0x00007f5527491793 in glXCreateContextAttribsARB () from /usr/lib/nvidia-352/libGL.so.1
#7 0x00007f5514fe4ab4 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#8 0x00007f5514fbd34b in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#9 0x00007f5529a3cbeb in QOpenGLContext::create() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#10 0x00007f5514fe513a in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#11 0x00007f5514fe52e1 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#12 0x00007f5518bfd62b in QSGRenderLoop::instance() () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#13 0x00007f5518c2de45 in QQuickWindowPrivate::init(QQuickWindow*, QQuickRenderControl*) ()
   from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#14 0x00007f5518cd90bd in QQuickView::QQuickView(QWindow*) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#15 0x00007f5518026a04 in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#16 0x00007f55180285e2 in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#17 0x00007f55180363a6 in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#18 0x00007f551803be0f in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#19 0x00007f551803c025 in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#20 0x00007f551f543d4e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#21 0x00007f551f547d5a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#22 0x00007f551f54881f in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#23 0x00007f551f54999e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#24 0x00007f5529715651 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007f5528144b8c in QApplicationPrivate::notify_helper(QObject*, QEvent*) ()
   from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007f552814a230 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#27 0x00007f55296e3f1b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x00007f55296e6057 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) ()
   from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#29 0x00007f552973ae73 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#30 0x00007f55261d4ff7 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007f55261d5250 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f55261d52fc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f552973b27f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#34 0x00007f55296e175a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#35 0x00007f55296e92cc in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#36 0x00007f551801dc86 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_ksmserver.so
#37 0x00000000004085a6 in ?? ()
#38 0x0000000000409e79 in ?? ()
#39 0x000000000040a513 in ?? ()
#40 0x00000000004050ac in main ()
(gdb)

This is probably the same bug reported here on the RedHat bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1238698 (might be informative)