Crash when exiting

[guihkx]

I didn't find a way to reproduce this crash yet, but looking at my system logs I noticed it happening a few times, so I'm using this issue to at least save some information about the crash.

This is on 75c876e with Qt 6.8.0 on Linux:

(gdb) bt
#0  NodeTreeItem::row (this=this@entry=0x30) at src/nodetreemodel.cpp:160
#1  0x00005a04bf1ca384 in NodeTreeModel::parent (this=0x5a04f2593960, index=...) at src/nodetreemodel.cpp:281
#2  0x00007875969713b3 in QModelIndex::parent (this=<optimized out>, this=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/itemmodels/qabstractitemmodel.h:506
#3  QItemSelection::select (this=0x7ffd8c1324f0, topLeft=..., bottomRight=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/itemmodels/qitemselectionmodel.cpp:395
#4  0x0000787596976e83 in QItemSelection::QItemSelection (this=0x7ffd8c1324f0, topLeft=..., bottomRight=...)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/itemmodels/qitemselectionmodel.cpp:379
#5  QItemSelectionModel::select (this=0x5a04f38028e0, index=..., command=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/itemmodels/qitemselectionmodel.cpp:1175
#6  0x00005a04bf1d7f1d in NodeTreeView::mouseReleaseEvent (this=0x5a04f2a73fc0, event=<optimized out>) at src/nodetreeview.cpp:593
#7  0x0000787598151276 in QWidget::event (this=0x5a04f2a73fc0, event=0x7ffd8c1328b0) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qwidget.cpp:8963
#8  0x00007875981edb48 in QFrame::event (this=0x5a04f2a73fc0, e=0x7ffd8c1328b0) at /usr/src/debug/qt6-base/qtbase/src/widgets/widgets/qframe.cpp:521
#9  0x0000787596755508 in QCoreApplicationPrivate::sendThroughObjectEventFilters (receiver=receiver@entry=0x5a04f29da1a0, event=event@entry=0x7ffd8c1328b0)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1304
#10 0x00007875980fe30a in QApplicationPrivate::notify_helper (this=this@entry=0x5a04f19eacb0, receiver=receiver@entry=0x5a04f29da1a0, e=e@entry=0x7ffd8c1328b0)
    at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:3288
#11 0x00007875981026ea in QApplication::notify (this=<optimized out>, receiver=<optimized out>, e=0x7ffd8c132b90) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:2772
#12 0x00007875967585a8 in QCoreApplication::notifyInternal2 (receiver=0x5a04f28bc190, event=0x7ffd8c132b90) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1165
#13 0x00007875967585fd in QCoreApplication::sendSpontaneousEvent (receiver=<optimized out>, event=<optimized out>)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1623
#14 0x00007875980f61bd in QApplicationPrivate::sendMouseEvent (receiver=0x5a04f28bc190, event=0x7ffd8c132b90, alienWidget=<optimized out>, nativeWidget=0x7ffd8c133440, 
    buttonDown=<optimized out>, lastMouseReceiver=..., spontaneous=true, onlyDispatchEnterLeave=false) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:2353
#15 0x000078759816a768 in QWidgetWindow::handleMouseEvent (this=0x5a04f29f2890, event=0x7ffd8c132e80) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qwidgetwindow.cpp:632
#16 QWidgetWindow::event (this=0x5a04f29f2890, event=0x7ffd8c132e80) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qwidgetwindow.cpp:298
#17 0x00007875980fe31a in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x5a04f29f2890, e=0x7ffd8c132e80)
    at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:3294
#18 0x00007875967585a8 in QCoreApplication::notifyInternal2 (receiver=0x5a04f29f2890, event=0x7ffd8c132e80) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1165
#19 0x00007875967585fd in QCoreApplication::sendSpontaneousEvent (receiver=<optimized out>, event=<optimized out>)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1623
#20 0x0000787596d85d4b in QGuiApplicationPrivate::processMouseEvent (e=0x78755802eda0) at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qguiapplication.cpp:2461
#21 0x0000787596e01284 in QWindowSystemInterface::sendWindowSystemEvents (flags=flags@entry=...) at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qwindowsysteminterface.cpp:1114
#22 0x00007875927eeb87 in xcbSourceDispatch (source=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/plugins/platforms/xcb/qxcbeventdispatcher.cpp:57
#23 0x000078759590d559 in g_main_dispatch (context=0x78758c000f30) at ../glib/glib/gmain.c:3357
#24 0x0000787595970157 in g_main_context_dispatch_unlocked (context=0x78758c000f30) at ../glib/glib/gmain.c:4208
#25 g_main_context_iterate_unlocked.isra.0 (context=context@entry=0x78758c000f30, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/glib/gmain.c:4273
#26 0x000078759590ca55 in g_main_context_iteration (context=0x78758c000f30, may_block=1) at ../glib/glib/gmain.c:4338
#27 0x00007875969bf71d in QEventDispatcherGlib::processEvents (this=0x5a04f1a6e960, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:396
#28 0x0000787596764566 in QEventLoop::processEvents (this=0x7ffd8c133350, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventloop.cpp:100
#29 QEventLoop::exec (this=0x7ffd8c133350, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventloop.cpp:191
#30 0x0000787596759a2f in QCoreApplication::exec () at /usr/src/debug/qt6-base/qtbase/src/corelib/global/qflags.h:74
#31 0x00007875980fa74a in QApplication::exec () at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:2562
#32 0x00005a04bf143e1e in main (argc=<optimized out>, argv=<optimized out>) at src/main.cpp:107
(gdb) list
155         }
156     }
157
158     int NodeTreeItem::row() const
159     {
160         if (m_parentItem) {
161             return m_parentItem->m_childItems.indexOf(const_cast<NodeTreeItem *>(this));
162         }
163
164         return 0;
(gdb) print &this->m_parentItem
$1 = (NodeTreeItem **) 0x50
(gdb)

The cause of the crash is clearly m_parentItem pointing to an invalid memory address (0x50) and then getting dereferenced, but I don't know yet how that happened or how to trigger it.

[nuttyartist]

Keep us posted !