Application: kmail (5.20.3 (22.04.3))
 (Compiled from sources)
Qt Version: 5.15.5
Frameworks Version: 5.96.0
Operating System: Linux 5.15.69-gentoo x86_64
Windowing System: X11
Distribution: "Gentoo Linux"
DrKonqi: 5.25.5 [KCrashBackend]

-- Information about the crash:
I'm running kmail from another machine via xpra/ssh session.
When I start dosbox in fullscreen, sometimes starting a game switches resolution multiple times, making dosbox going forth and back from fullscreen to windowed.
Kmail crashes reliably during these wild screen changes. (Simple screen change during dosbox startup/close isn't enough to trigger the crash.)

The crash can be reproduced sometimes.

-- Backtrace:
Application: KMail (kmail), signal: Aborted
Content of s_kcrashErrorMessage: std::unique_ptr<char []> = {get() = 0x0}
[KCrash Handler]
#6  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#7  0x00007f4a64426ecf in __pthread_kill_internal (signo=6, threadid=<optimized out>) at pthread_kill.c:78
#8  0x00007f4a643db6a2 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#9  0x00007f4a643c6469 in __GI_abort () at abort.c:79
#10 0x00007f4a6441b278 in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7f4a6454d7be "%s\n") at ../sysdeps/posix/libc_fatal.c:155
#11 0x00007f4a644309da in malloc_printerr (str=str@entry=0x7f4a6454b1e1 "free(): invalid pointer") at malloc.c:5664
#12 0x00007f4a6443256c in _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:4439
#13 0x00007f4a644350bf in __GI___libc_free (mem=<optimized out>) at malloc.c:3391
#14 0x00007f4a642e20ef in QTypedArrayData<unsigned short>::deallocate(QArrayData*) (data=<optimized out>) at /usr/include/qt5/QtCore/qarraydata.h:237
#15 QString::~QString() (this=0x7ffd6d0f5700, __in_chrg=<optimized out>) at /usr/include/qt5/QtCore/qstring.h:1311
#16 QString::~QString() (this=0x7ffd6d0f5700, __in_chrg=<optimized out>) at /usr/include/qt5/QtCore/qstring.h:1311
#17 KToolTipHelperPrivate::handleToolTipEvent(QWidget*, QHelpEvent*) (this=0x55b4271b3550, watchedWidget=<optimized out>, helpEvent=0x7ffd6d0f5ae0) at /var/tmp/portage/kde-frameworks/kxmlgui-5.96.0/work/kxmlgui-5.96.0/src/ktooltiphelper.cpp:210
#18 0x00007f4a64a34d21 in QCoreApplicationPrivate::sendThroughApplicationEventFilters(QObject*, QEvent*) (event=<optimized out>, receiver=<optimized out>, this=<optimized out>) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qcoreapplication.cpp:1172
#19 QCoreApplicationPrivate::sendThroughApplicationEventFilters(QObject*, QEvent*) (this=this@entry=0x55b426c35e70, receiver=receiver@entry=0x55b429a6cc80, event=event@entry=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qcoreapplication.cpp:1157
#20 0x00007f4a653f2758 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=0x55b426c35e70, receiver=0x55b429a6cc80, e=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:3608
#21 0x00007f4a64a35068 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x55b429a6cc80, event=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qcoreapplication.cpp:1064
#22 0x00007f4a65798506 in QSystemTrayIconSys::event(QEvent*) (this=0x55b429a6c150, e=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/util/qsystemtrayicon_x11.cpp:154
#23 0x00007f4a653f271f in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=0x55b426c35e70, receiver=receiver@entry=0x55b429a6c150, e=e@entry=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:3637
#24 0x00007f4a653fb040 in QApplication::notify(QObject*, QEvent*) (this=<optimized out>, receiver=0x55b429a6c150, e=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:3303
#25 0x00007f4a64a35068 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x55b429a6c150, event=0x7ffd6d0f5ae0) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qcoreapplication.cpp:1064
#26 0x00007f4a653f80e9 in QApplication::event(QEvent*) (this=0x7ffd6d0f6370, e=0x7ffd6d0f5c00) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:1901
#27 0x00007f4a653f271f in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=<optimized out>, receiver=0x7ffd6d0f6370, e=0x7ffd6d0f5c00) at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:3637
#28 0x00007f4a64a35068 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x7ffd6d0f6370, event=0x7ffd6d0f5c00) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qcoreapplication.cpp:1064
#29 0x00007f4a64a845cb in QTimerInfoList::activateTimers() (this=0x55b426cf5660) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qtimerinfo_unix.cpp:643
#30 0x00007f4a64a84eac in timerSourceDispatch (source=<optimized out>) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qeventdispatcher_glib.cpp:183
#31 idleTimerSourceDispatch(GSource*, GSourceFunc, gpointer) (source=<optimized out>) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qeventdispatcher_glib.cpp:230
#32 0x00007f4a5e7c4b8b in g_main_dispatch (context=0x7f4a50005010) at ../glib-2.72.3/glib/gmain.c:3417
#33 g_main_context_dispatch (context=0x7f4a50005010) at ../glib-2.72.3/glib/gmain.c:4135
#34 0x00007f4a5e7c4e38 in g_main_context_iterate (context=context@entry=0x7f4a50005010, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib-2.72.3/glib/gmain.c:4211
#35 0x00007f4a5e7c4eef in g_main_context_iteration (context=0x7f4a50005010, may_block=1) at ../glib-2.72.3/glib/gmain.c:4276
#36 0x00007f4a64a85268 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55b426ceca90, flags=...) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/src/corelib/kernel/qeventdispatcher_glib.cpp:423
#37 0x00007f4a64a33af3 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7ffd6d0f5e40, flags=..., flags@entry=...) at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/include/QtCore/../../src/corelib/global/qflags.h:69
#38 0x00007f4a64a3bde0 in QCoreApplication::exec() () at /var/tmp/portage/dev-qt/qtcore-5.15.5-r3/work/qtbase-everywhere-src-5.15.5/include/QtCore/../../src/corelib/global/qflags.h:121
#39 0x00007f4a64e1a39c in QGuiApplication::exec() () at /var/tmp/portage/dev-qt/qtgui-5.15.5-r2/work/qtbase-everywhere-src-5.15.5/src/gui/kernel/qguiapplication.cpp:1867
#40 0x00007f4a653f2695 in QApplication::exec() () at /var/tmp/portage/dev-qt/qtwidgets-5.15.5-r1/work/qtbase-everywhere-src-5.15.5/src/widgets/kernel/qapplication.cpp:2829
#41 0x000055b426013aa5 in main(int, char**) (argc=<optimized out>, argv=<optimized out>) at /var/tmp/portage/kde-apps/kmail-22.04.3/work/kmail-22.04.3/src/main.cpp:174
[Inferior 1 (process 7400) detached]

Reported using DrKonqi