Application: systemsettings5 (5.5.5)

Qt Version: 5.5.1
Operating System: Linux 4.4.0-53-generic x86_64
Distribution: Ubuntu 16.04.1 LTS

-- Information about the crash:
- What I was doing when the application crashed:
I tried to check config of touchpad in system-settings because touchpad stopped working after update
- Unusual behavior I noticed:
touchpad stopped working, although correctly wporking before update
if I clicked between mouse and touchpad system-settings crashed
tried reinstalling with sudo aptitude install xserver-xorg-input-synaptics-lts-xenial
restarted x-server => no change 
tried installing with sudo aptitude install xserver-xorg-input-libinput
restarted x-server => no change

The crash can be reproduced sometimes.

-- Backtrace:
Application: Systemeinstellungen (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f4098dd48c0 (LWP 7682))]

Thread 2 (Thread 0x7f40883cc700 (LWP 7683)):
#0  0x00007f40954f7b5d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f40931dfc62 in poll (__timeout=-1, __nfds=1, __fds=0x7f40883cbc00) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0xbc8b70, cond=cond@entry=0xbc8bb0, vector=vector@entry=0x0, count=count@entry=0x0) at ../../src/xcb_conn.c:459
#3  0x00007f40931e18d7 in xcb_wait_for_event (c=0xbc8b70) at ../../src/xcb_in.c:693
#4  0x00007f408ad50629 in QXcbEventReader::run (this=0xbd4f00) at qxcbconnection.cpp:1253
#5  0x00007f4095bed7be in QThreadPrivate::start (arg=0xbd4f00) at thread/qthread_unix.cpp:331
#6  0x00007f40929696ba in start_thread (arg=0x7f40883cc700) at pthread_create.c:333
#7  0x00007f409550382d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f4098dd48c0 (LWP 7682)):
[KCrash Handler]
#6  xcb_wait_for_reply (c=0x0, request=2861929877, e=e@entry=0x0) at ../../src/xcb_in.c:542
#7  0x00007f40931e5a55 in xcb_intern_atom_reply (c=<optimized out>, cookie=..., e=e@entry=0x0) at xproto.c:2143
#8  0x00007f407747b2bc in XcbAtom::atom (this=this@entry=0x1254180) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xcbatom.cpp:49
#9  0x00007f407747c3ed in XlibBackend::findTouchpad (this=this@entry=0x1254120, identifier=...) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xlibbackend.cpp:378
#10 0x00007f407747c871 in XlibBackend::devicePlugged (this=0x1254120, device=11) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xlibbackend.cpp:703
#11 0x00007f4095dfcd2a in QMetaObject::activate (sender=sender@entry=0x3a5c880, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x7ffc49d0a2e0) at kernel/qobject.cpp:3713
#12 0x00007f4095dfd537 in QMetaObject::activate (sender=sender@entry=0x3a5c880, m=m@entry=0x7f4077695be0 <XlibNotifications::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x7ffc49d0a2e0) at kernel/qobject.cpp:3578
#13 0x00007f4077484664 in XlibNotifications::devicePlugged (_t1=11, this=0x3a5c880) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/obj-x86_64-linux-gnu/kcms/touchpad/src/moc_xlibnotifications.cpp:162
#14 XlibNotifications::processEvent (this=this@entry=0x3a5c880, event=event@entry=0x7ffc49d0a340) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xlibnotifications.cpp:144
#15 0x00007f407748493c in XlibNotifications::processEvent (event=0x7ffc49d0a340, this=0x3a5c880) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xlibnotifications.cpp:110
#16 XlibNotifications::processEvents (this=this@entry=0x3a5c880) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/kcms/touchpad/src/backends/x11/xlibnotifications.cpp:82
#17 0x00007f40774849ba in XlibNotifications::qt_static_metacall (_o=_o@entry=0x3a5c880, _c=_c@entry=QMetaObject::InvokeMetaMethod, _id=_id@entry=3, _a=_a@entry=0x7ffc49d0a580) at /build/plasma-desktop-Bvo2Ad/plasma-desktop-5.5.5/obj-x86_64-linux-gnu/kcms/touchpad/src/moc_xlibnotifications.cpp:88
#18 0x00007f4095dfcd2a in QMetaObject::activate (sender=sender@entry=0x3ab8f50, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffc49d0a580) at kernel/qobject.cpp:3713
#19 0x00007f4095dfd537 in QMetaObject::activate (sender=sender@entry=0x3ab8f50, m=m@entry=0x7f4096017780 <QSocketNotifier::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffc49d0a580) at kernel/qobject.cpp:3578
#20 0x00007f4095e7c24e in QSocketNotifier::activated (this=this@entry=0x3ab8f50, _t1=18) at .moc/moc_qsocketnotifier.cpp:134
#21 0x00007f4095e091cb in QSocketNotifier::event (this=0x3ab8f50, e=<optimized out>) at kernel/qsocketnotifier.cpp:260
#22 0x00007f40972a105c in QApplicationPrivate::notify_helper (this=this@entry=0xbba2e0, receiver=receiver@entry=0x3ab8f50, e=e@entry=0x7ffc49d0a7f0) at kernel/qapplication.cpp:3716
#23 0x00007f40972a6516 in QApplication::notify (this=0x7ffc49d0ab20, receiver=0x3ab8f50, e=0x7ffc49d0a7f0) at kernel/qapplication.cpp:3499
#24 0x00007f4095dce38b in QCoreApplication::notifyInternal (this=0x7ffc49d0ab20, receiver=0x3ab8f50, event=event@entry=0x7ffc49d0a7f0) at kernel/qcoreapplication.cpp:965
#25 0x00007f4095e24c95 in QCoreApplication::sendEvent (event=0x7ffc49d0a7f0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:224
#26 socketNotifierSourceDispatch (source=0xc041a0) at kernel/qeventdispatcher_glib.cpp:101
#27 0x00007f40924481a7 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#28 0x00007f4092448400 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007f40924484ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#30 0x00007f4095e247cf in QEventDispatcherGlib::processEvents (this=0xbfdb80, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#31 0x00007f4095dcbb4a in QEventLoop::exec (this=this@entry=0x7ffc49d0aa00, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#32 0x00007f4095dd3bec in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1229
#33 0x00007f4096ce7bfc in QGuiApplication::exec () at kernel/qguiapplication.cpp:1542
#34 0x00007f409729d495 in QApplication::exec () at kernel/qapplication.cpp:2976
#35 0x000000000040f7a1 in main (argc=1, argv=<optimized out>) at /build/systemsettings-3AmRXd/systemsettings-5.5.5/app/main.cpp:55

Reported using DrKonqi