Application: kwin_x11 (5.9.4)

Qt Version: 5.7.1
Frameworks Version: 5.31.0
Operating System: Linux 4.10.0-21-generic x86_64
Distribution: Ubuntu 17.04

-- Information about the crash:
I was changing audio from Pulse to ALSA for a Windows 10 guest and then it crashed.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f79c1bff580 (LWP 8128))]

Thread 7 (Thread 0x7f7967819700 (LWP 8140)):
#0  0x00007f79bad2d510 in pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f79be0582c4 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f79be058309 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f79bad276da in start_thread (arg=0x7f7967819700) at pthread_create.c:456
#4  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 6 (Thread 0x7f796cd1b700 (LWP 8139)):
#0  0x00007f79bad2d8b9 in pthread_cond_timedwait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:225
#1  0x00007f79beccfa86 in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f79beccb2b2 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f79beccec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f79bad276da in start_thread (arg=0x7f796cd1b700) at pthread_create.c:456
#5  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 5 (Thread 0x7f7985542700 (LWP 8137)):
#0  0x00007f79c1627251 in __GI_ppoll (fds=0x7f7980000ac8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f79beeee251 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f79beeefb4a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f79bee9c88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f79becc9fe3 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f79b9a94df5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f79beccec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f79bad276da in start_thread (arg=0x7f7985542700) at pthread_create.c:456
#8  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 4 (Thread 0x7f799efbd700 (LWP 8136)):
#0  0x00007f79c1627251 in __GI_ppoll (fds=0x7f798c000ac8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f79beeee251 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f79beeefb4a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f79bee9c88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f79becc9fe3 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f79b9a94df5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f79beccec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f79bad276da in start_thread (arg=0x7f799efbd700) at pthread_create.c:456
#8  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 3 (Thread 0x7f799fded700 (LWP 8134)):
#0  0x00007f79bad2d8b9 in pthread_cond_timedwait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:225
#1  0x00007f79beccfa86 in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f79beccb2b2 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f79beccec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f79bad276da in start_thread (arg=0x7f799fded700) at pthread_create.c:456
#5  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 2 (Thread 0x7f79a83eb700 (LWP 8131)):
#0  0x00007f79c1627251 in __GI_ppoll (fds=0x7f79a000d5a8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f79beeee251 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f79beeefb4a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f79bee9c88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f79becc9fe3 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f79b8c6d5c5 in  () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#6  0x00007f79beccec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f79bad276da in start_thread (arg=0x7f79a83eb700) at pthread_create.c:456
#8  0x00007f79c163317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 1 (Thread 0x7f79c1bff580 (LWP 8128)):
[KCrash Handler]
#6  0x0000000000000000 in  ()
#7  0x00007f79beed06e0 in QObject::connect(QObject const*, char const*, QObject const*, char const*, Qt::ConnectionType) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f79be099037 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#9  0x00007f79be0990ff in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#10 0x00007f79be099382 in QScriptEngine::newQObject(QObject*, QScriptEngine::ValueOwnership, QFlags<QScriptEngine::QObjectWrapOption> const&) () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#11 0x00007f79c120f95f in  () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#12 0x00007f79be0995e5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#13 0x00007f79be0c0bf6 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#14 0x00007f79be0c8ba1 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#15 0x00007f79beeca644 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007f79be689e28 in KWin::EffectsHandler::desktopPresenceChanged(KWin::EffectWindow*, int, int) () at /usr/lib/x86_64-linux-gnu/libkwineffects.so.10
#17 0x00007f79be68b7f1 in  () at /usr/lib/x86_64-linux-gnu/libkwineffects.so.10
#18 0x00007f79beecb359 in QObject::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007f79bfb7635c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#20 0x00007f79bfb7db11 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#21 0x00007f79bee9e8a0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f79beea102d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f79beeef977 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007f79a74a29fd in  () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#25 0x00007f79bee9c88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007f79beea4ffc in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#27 0x00007f79c18fb112 in kdemain () at /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#28 0x00007f79c154b3f1 in __libc_start_main (main=0x55c34e1f17e0, argc=3, argv=0x7ffc3b8c7418, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc3b8c7408) at ../csu/libc-start.c:291
#29 0x000055c34e1f181a in _start ()

Reported using DrKonqi