Application: kmail (4.14.10)
KDE Platform Version: 4.14.10
Qt Version: 4.8.7
Operating System: Linux 4.1.0-2-amd64 x86_64
Distribution: Debian GNU/Linux testing (stretch)

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

clicked Settings -> Configure KMail -> Appearance

running Plasma 5.4.0

The crash can be reproduced every time.

-- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f6f925bd940 (LWP 8476))]

Thread 5 (Thread 0x7f6f697ad700 (LWP 8479)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f6f84a32bed in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f6f84a32c49 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f6f87cea0a4 in start_thread (arg=0x7f6f697ad700) at pthread_create.c:309
#4  0x00007f6f8f82c07d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f6f23ffd700 (LWP 8480)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f6f84756361 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f6f84a63386 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f6f87cea0a4 in start_thread (arg=0x7f6f23ffd700) at pthread_create.c:309
#4  0x00007f6f8f82c07d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f6f237fc700 (LWP 8488)):
#0  QMutex::lockInline (this=0x2058118) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:187
#1  QMutexLocker::QMutexLocker (m=0x2058118, this=<synthetic pointer>) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:109
#2  QThreadData::canWaitLocked (this=0x20580d0) at ../../include/QtCore/private/../../../src/corelib/thread/qthread_p.h:228
#3  postEventSourcePrepare (s=0x7f6f14001300, timeout=0x7f6f237fbac4) at kernel/qeventdispatcher_glib.cpp:263
#4  0x00007f6f8740a3fd in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f6f8740ade8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007f6f8740afcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007f6f90f2c406 in QEventDispatcherGlib::processEvents (this=0x7f6f140008e0, flags=...) at kernel/qeventdispatcher_glib.cpp:427
#8  0x00007f6f90efa331 in QEventLoop::processEvents (this=this@entry=0x7f6f237fbc90, flags=...) at kernel/qeventloop.cpp:149
#9  0x00007f6f90efa6a5 in QEventLoop::exec (this=this@entry=0x7f6f237fbc90, flags=...) at kernel/qeventloop.cpp:204
#10 0x00007f6f90de9579 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:538
#11 0x00007f6f90debe6c in QThreadPrivate::start (arg=0x1c6c210) at thread/qthread_unix.cpp:352
#12 0x00007f6f87cea0a4 in start_thread (arg=0x7f6f237fc700) at pthread_create.c:309
#13 0x00007f6f8f82c07d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f6f19ecb700 (LWP 8515)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f6f7a42ae0a in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f6f7a42ae39 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f6f87cea0a4 in start_thread (arg=0x7f6f19ecb700) at pthread_create.c:309
#4  0x00007f6f8f82c07d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f6f925bd940 (LWP 8476)):
[KCrash Handler]
#6  QScopedPointer<QObjectData, QScopedPointerDeleter<QObjectData> >::data (this=<optimized out>) at ../../include/QtCore/../../src/corelib/tools/qscopedpointer.h:135
#7  qGetPtrHelper<QScopedPointer<QObjectData> > (p=...) at ../../include/QtCore/../../src/corelib/global/qglobal.h:2582
#8  QAbstractButton::d_func (this=<optimized out>) at widgets/qabstractbutton.h:171
#9  QAbstractButton::setChecked (this=0x0, checked=true) at widgets/qabstractbutton.cpp:738
#10 0x00007f6f9216fc8d in ConfigModuleTab::load (this=0x2775d80) at ../../kmail/configuredialog/configuredialog_p.cpp:82
#11 ConfigModuleWithTabs::load (this=0x270db10) at ../../kmail/configuredialog/configuredialog_p.cpp:52
#12 0x00007f6f91a51229 in KCModule::qt_static_metacall (_o=<optimized out>, _id=<optimized out>, _a=<optimized out>, _c=<optimized out>) at ./kcmodule.moc:65
#13 0x00007f6f90f15f61 in QObject::event (this=this@entry=0x270db10, e=e@entry=0x2761600) at kernel/qobject.cpp:1222
#14 0x00007f6f9029b62c in QWidget::event (this=0x270db10, event=0x2761600) at kernel/qwidget.cpp:8859
#15 0x00007f6f902448dc in QApplicationPrivate::notify_helper (this=this@entry=0x168cca0, receiver=receiver@entry=0x270db10, e=e@entry=0x2761600) at kernel/qapplication.cpp:4570
#16 0x00007f6f9024b816 in QApplication::notify (this=this@entry=0x7ffd140b7350, receiver=receiver@entry=0x270db10, e=e@entry=0x2761600) at kernel/qapplication.cpp:4356
#17 0x00007f6f919b571a in KApplication::notify (this=0x7ffd140b7350, receiver=0x270db10, event=0x2761600) at ../../kdeui/kernel/kapplication.cpp:311
#18 0x00007f6f90efbabd in QCoreApplication::notifyInternal (this=0x7ffd140b7350, receiver=receiver@entry=0x270db10, event=event@entry=0x2761600) at kernel/qcoreapplication.cpp:955
#19 0x00007f6f90eff576 in QCoreApplication::sendEvent (event=0x2761600, receiver=0x270db10) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#20 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x15cc1b0) at kernel/qcoreapplication.cpp:1579
#21 0x00007f6f90eff853 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1472
#22 0x00007f6f90f2c293 in QCoreApplication::sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#23 postEventSourceDispatch (s=0x15cf520) at kernel/qeventdispatcher_glib.cpp:280
#24 0x00007f6f8740ac3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#25 0x00007f6f8740af20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#26 0x00007f6f8740afcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#27 0x00007f6f90f2c3e4 in QEventDispatcherGlib::processEvents (this=0x168a1a0, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#28 0x00007f6f902eea36 in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#29 0x00007f6f90efa331 in QEventLoop::processEvents (this=this@entry=0x7ffd140b6f90, flags=...) at kernel/qeventloop.cpp:149
#30 0x00007f6f90efa6a5 in QEventLoop::exec (this=this@entry=0x7ffd140b6f90, flags=...) at kernel/qeventloop.cpp:204
#31 0x00007f6f90f00689 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1227
#32 0x00007f6f9024306c in QApplication::exec () at kernel/qapplication.cpp:3828
#33 0x0000000000402eee in main (argc=3, argv=0x7ffd140b7578) at ../../kmail/main.cpp:145

Reported using DrKonqi