Application: okular (0.26.1)
KDE Platform Version: 4.14.26
Qt Version: 4.8.7
Operating System: Linux 4.9.0-3-amd64 x86_64
Distribution: Debian GNU/Linux testing (buster)

-- Information about the crash:
- What I was doing when the application crashed:
I was closing Okular after viewing an octet-stream mime-type file downloaded with Firefox ESR. The file wasn't a PDF file.

-- Backtrace:
Application: Okular (okular), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[KCrash Handler]
#6  0x00007f3575964fcf in raise () at /lib/x86_64-linux-gnu/libc.so.6
#7  0x00007f35759663fa in abort () at /lib/x86_64-linux-gnu/libc.so.6
#8  0x00007f35759a2bd0 in  () at /lib/x86_64-linux-gnu/libc.so.6
#9  0x00007f35759a8f96 in  () at /lib/x86_64-linux-gnu/libc.so.6
#10 0x00007f35759a97de in  () at /lib/x86_64-linux-gnu/libc.so.6
#11 0x00007f3576478894 in QObjectPrivate::deleteChildren() () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#12 0x00007f3576ed6862 in QWidget::~QWidget() () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#13 0x00007f35677827de in  () at /usr/lib/kde4/okularpart.so
#14 0x00007f3567782919 in  () at /usr/lib/kde4/okularpart.so
#15 0x00007f3567718b78 in Okular::Part::~Part() () at /usr/lib/kde4/okularpart.so
#16 0x00007f3567718eb9 in Okular::Part::~Part() () at /usr/lib/kde4/okularpart.so
#17 0x00007f3576478894 in QObjectPrivate::deleteChildren() () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#18 0x00007f3576ed6862 in QWidget::~QWidget() () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#19 0x00007f3577cc201b in KMainWindow::~KMainWindow() () at /usr/lib/libkdeui.so.5
#20 0x0000564be16dff58 in  ()
#21 0x0000564be16e0049 in  ()
#22 0x00007f357647a3a8 in QObject::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#23 0x00007f3576ed72ec in QWidget::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#24 0x00007f35772b6803 in QMainWindow::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#25 0x00007f3577d019e9 in KXmlGuiWindow::event(QEvent*) () at /usr/lib/libkdeui.so.5
#26 0x00007f3576e8054c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#27 0x00007f3576e8752c in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#28 0x00007f3577bfdc5a in KApplication::notify(QObject*, QEvent*) () at /usr/lib/libkdeui.so.5
#29 0x00007f357645ff1d in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#30 0x00007f3576463a16 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#31 0x00007f3576490703 in  () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#32 0x00007f357285ca17 in g_main_dispatch (context=0x564be33160e0) at ././glib/gmain.c:3234
#33 0x00007f357285ca17 in g_main_context_dispatch (context=context@entry=0x564be33160e0) at ././glib/gmain.c:3899
#34 0x00007f357285cc80 in g_main_context_iterate (context=context@entry=0x564be33160e0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ././glib/gmain.c:3972
#35 0x00007f357285cd2c in g_main_context_iteration (context=0x564be33160e0, may_block=1) at ././glib/gmain.c:4033
#36 0x00007f3576490854 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#37 0x00007f3576f2a5d6 in  () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#38 0x00007f357645e7ef in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#39 0x00007f357645eb55 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#40 0x00007f35772df567 in QMenu::exec(QPoint const&, QAction*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#41 0x00007f356778687d in  () at /usr/lib/kde4/okularpart.so
#42 0x00007f3576ed6e80 in QWidget::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#43 0x00007f357729bc8e in QFrame::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#44 0x00007f3567788096 in  () at /usr/lib/kde4/okularpart.so
#45 0x00007f35764600a1 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#46 0x00007f3576e8052c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#47 0x00007f3576e88ca7 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#48 0x00007f3577bfdc5a in KApplication::notify(QObject*, QEvent*) () at /usr/lib/libkdeui.so.5
#49 0x00007f357645ff1d in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#50 0x00007f3576e86ccb in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#51 0x00007f3576f021a9 in  () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#52 0x00007f3576f00b5c in QApplication::x11ProcessEvent(_XEvent*) () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#53 0x00007f3576f2a502 in  () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#54 0x00007f357285ca17 in g_main_dispatch (context=0x564be33160e0) at ././glib/gmain.c:3234
#55 0x00007f357285ca17 in g_main_context_dispatch (context=context@entry=0x564be33160e0) at ././glib/gmain.c:3899
#56 0x00007f357285cc80 in g_main_context_iterate (context=context@entry=0x564be33160e0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ././glib/gmain.c:3972
#57 0x00007f357285cd2c in g_main_context_iteration (context=0x564be33160e0, may_block=1) at ././glib/gmain.c:4033
#58 0x00007f3576490854 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#59 0x00007f3576f2a5d6 in  () at /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#60 0x00007f357645e7ef in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#61 0x00007f357645eb55 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#62 0x00007f3576464bd9 in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#63 0x0000564be16d92a3 in  ()
#64 0x00007f35759522b1 in __libc_start_main () at /lib/x86_64-linux-gnu/libc.so.6
#65 0x0000564be16daf6a in _start ()

Reported using DrKonqi