Bug 423682

Application: systemsettings5 (5.19.2)

Qt Version: 5.14.2
Frameworks Version: 5.71.0
Operating System: Linux 5.8.0-0.rc3.1.fc33.x86_64 x86_64
Windowing system: Wayland
Distribution: Fedora 33 (KDE Plasma Prerelease)

-- Information about the crash:
- What I was doing when the application crashed:

I was using Plasma 5.19.2 on Wayland in a Fedora Rawhide KDE Plasma spin installation with KF 5.71.0, Qt 5.14.2. I started System Settings on Wayland. I selected Workspace Behavior > Activities. The left menus were black as I reported at https://bugs.kde.org/show_bug.cgi?id=418291 The main part of System Settings wasn't displaying normally. I closed System Settings. A segmentation fault in System Settings happened in QtWaylandClient::QWaylandWindow::decoration at qwaylandwindow.cpp:825. this=0x0 in QtWaylandClient::QWaylandWindow::decoration might indicate a null pointer dereference as the reason for the segmentation fault. qwaylandwindow.cpp:825 returns mWindowDecoration in QtWaylandClient::QWaylandWindow::decoration

QWaylandAbstractDecoration *QWaylandWindow::decoration() const
{
    return mWindowDecoration;
}

-- Backtrace:
Application: System Settings (systemsettings5), signal: Segmentation fault

[KCrash Handler]
#4  QtWaylandClient::QWaylandWindow::decoration (this=0x0) at qwaylandwindow.cpp:825
#5  0x00007f31b8a01759 in QtWaylandClient::QWaylandShmBackingStore::windowDecoration (this=this@entry=0x5623ea6448c0) at qwaylandshmbackingstore.cpp:362
#6  0x00007f31b8a021c6 in QtWaylandClient::QWaylandShmBackingStore::resize (this=this@entry=0x5623ea6448c0, size=...) at qwaylandshmbackingstore.cpp:308
#7  0x00007f31b8a02301 in QtWaylandClient::QWaylandShmBackingStore::ensureSize (this=this@entry=0x5623ea6448c0) at qwaylandshmbackingstore.cpp:205
#8  0x00007f31b8a0233d in QtWaylandClient::QWaylandShmBackingStore::beginPaint (this=this@entry=0x5623ea6448c0, region=...) at qwaylandshmbackingstore.cpp:180
#9  0x00007f31cb08ddad in QBackingStore::beginPaint (this=0x5623ea6bc0c0, region=...) at ../../include/QtGui/5.14.2/QtGui/private/../../../../../src/gui/kernel/qhighdpiscaling_p.h:109
#10 0x00007f31cb4f3e0e in QWidgetRepaintManager::paintAndFlush (this=<optimized out>) at kernel/qwidgetrepaintmanager.cpp:984
#11 0x00007f31cb524a97 in QWidget::event (this=this@entry=0x5623ea4b5020, event=event@entry=0x5623ec3b09d0) at kernel/qwidget.cpp:8978
#12 0x00007f31cb633530 in QMainWindow::event (this=this@entry=0x5623ea4b5020, event=event@entry=0x5623ec3b09d0) at widgets/qmainwindow.cpp:1341
#13 0x00007f31cbfabf4d in KMainWindow::event (this=this@entry=0x5623ea4b5020, ev=ev@entry=0x5623ec3b09d0) at /usr/src/debug/kf5-kxmlgui-5.71.0-1.fc33.x86_64/src/kmainwindow.cpp:885
#14 0x00007f31cbfdac3d in KXmlGuiWindow::event (this=0x5623ea4b5020, ev=0x5623ec3b09d0) at /usr/src/debug/kf5-kxmlgui-5.71.0-1.fc33.x86_64/src/kxmlguiwindow.cpp:121
#15 0x00007f31cb4e3063 in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x5623ea4b5020, e=0x5623ec3b09d0) at kernel/qapplication.cpp:3685
#16 0x00007f31caaabfc0 in QCoreApplication::notifyInternal2 (receiver=0x5623ea4b5020, event=0x5623ec3b09d0) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:153
#17 0x00007f31caaaec47 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x5623ea44b000) at kernel/qcoreapplication.cpp:1815
#18 0x00007f31caaf80a7 in postEventSourceDispatch (s=s@entry=0x5623ea466630) at kernel/qeventdispatcher_glib.cpp:277
#19 0x00007f31c882beaf in g_main_dispatch (context=0x5623ea47aa30) at ../glib/gmain.c:3309
#20 g_main_context_dispatch (context=0x5623ea47aa30) at ../glib/gmain.c:3974
#21 0x00007f31c882c238 in g_main_context_iterate (context=context@entry=0x5623ea47aa30, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4047
#22 0x00007f31c882c303 in g_main_context_iteration (context=0x5623ea47aa30, may_block=may_block@entry=1) at ../glib/gmain.c:4108
#23 0x00007f31caaf7b73 in QEventDispatcherGlib::processEvents (this=0x5623ea49d2f0, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#24 0x00007f31caaaa91b in QEventLoop::exec (this=this@entry=0x7fff34ad2850, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:136
#25 0x00007f31caab25a6 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:118
#26 0x00005623e98290cf in main (argc=<optimized out>, argv=0x7fff34ad2970) at /usr/src/debug/plasma-systemsettings-5.19.2-1.fc33.x86_64/app/main.cpp:168
[Inferior 1 (process 9398) detached]

Reported using DrKonqi