Application: kwin_x11 (5.10.4)

Qt Version: 5.9.1
Frameworks Version: 5.36.0
Operating System: Linux 4.12.4-1.g2a27bf2-default x86_64
Distribution: "openSUSE Tumbleweed"

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

Qt Assitant was suddenly frozen for some reason with 1 cpu full load, so I decided to try to close it via closing the window.
1. Clicked the "Close" button of the Assistant window
2. Title bar turned to "Qt Assistant (Not reponding)"
3. a few seconds me starring at screen waiting if anything else happens, not doing any input

Then kwin crashes, but Qt Assistant also is gone at the time kwin has restarted

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
84	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
[Current thread is 1 (Thread 0x7fc4b4e14900 (LWP 1817))]

Thread 5 (Thread 0x7fc492118700 (LWP 1927)):
#0  0x00007fc4ad9da5dd in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fc4b1020fb8 <QTWTF::pageheap_memory+57592>) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007fc4ad9da5dd in __pthread_cond_wait_common (abstime=0x0, mutex=0x7fc4b1020f68 <QTWTF::pageheap_memory+57512>, cond=0x7fc4b1020f90 <QTWTF::pageheap_memory+57552>) at pthread_cond_wait.c:502
#2  0x00007fc4ad9da5dd in __pthread_cond_wait (cond=0x7fc4b1020f90 <QTWTF::pageheap_memory+57552>, mutex=0x7fc4b1020f68 <QTWTF::pageheap_memory+57512>) at pthread_cond_wait.c:655
#3  0x00007fc4b0d2a8e4 in QTWTF::TCMalloc_PageHeap::scavengerThread() (this=0x7fc4b1012ec0 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#4  0x00007fc4b0d2a929 in QTWTF::TCMalloc_PageHeap::runScavengerThread(void*) (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#5  0x00007fc4ad9d44d7 in start_thread (arg=0x7fc492118700) at pthread_create.c:456
#6  0x00007fc4b47b5b2f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

Thread 4 (Thread 0x7fc49352d700 (LWP 1915)):
#0  0x00007fc4b47ac266 in __GI_ppoll (fds=0x7fc480000ac8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007fc4b1dd4649 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007fc4b1dd5c26 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#3  0x00007fc4b1d8135a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007fc4b1bb131a in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#5  0x00007fc4ac4dd705 in  () at /usr/lib64/libQt5Qml.so.5
#6  0x00007fc4b1bb5d2e in QThreadPrivate::start(void*) () at /usr/lib64/libQt5Core.so.5
#7  0x00007fc4ad9d44d7 in start_thread (arg=0x7fc49352d700) at pthread_create.c:456
#8  0x00007fc4b47b5b2f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

Thread 3 (Thread 0x7fc499a6d700 (LWP 1847)):
#0  0x00007fc4b47ac266 in __GI_ppoll (fds=0x7fc48c00aa68, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007fc4b1dd4649 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007fc4b1dd5c26 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#3  0x00007fc4b1d8135a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007fc4b1bb131a in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#5  0x00007fc4ab6a4a45 in QDBusConnectionManager::run() () at /usr/lib64/libQt5DBus.so.5
#6  0x00007fc4b1bb5d2e in QThreadPrivate::start(void*) () at /usr/lib64/libQt5Core.so.5
#7  0x00007fc4ad9d44d7 in start_thread (arg=0x7fc499a6d700) at pthread_create.c:456
#8  0x00007fc4b47b5b2f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

Thread 2 (Thread 0x7fc49bc07700 (LWP 1837)):
#0  0x00007fc4b47ac18d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fc4b38d1387 in  () at /usr/lib64/libxcb.so.1
#2  0x00007fc4b38d316a in xcb_wait_for_event () at /usr/lib64/libxcb.so.1
#3  0x00007fc49ccfb449 in  () at /usr/lib64/libQt5XcbQpa.so.5
#4  0x00007fc4b1bb5d2e in QThreadPrivate::start(void*) () at /usr/lib64/libQt5Core.so.5
#5  0x00007fc4ad9d44d7 in start_thread (arg=0x7fc49bc07700) at pthread_create.c:456
#6  0x00007fc4b47b5b2f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

Thread 1 (Thread 0x7fc4b4e14900 (LWP 1817)):
[KCrash Handler]
#6  0x00007fc4b4a69038 in main_arena () at /lib64/libc.so.6
#7  0x00007fc4b42bd14d in KWin::Workspace::constrainedStackingOrder() () at /usr/lib64/libkwin.so.5
#8  0x00007fc4b42bd918 in KWin::Workspace::updateStackingOrder(bool) () at /usr/lib64/libkwin.so.5
#9  0x00007fc4b42bdc10 in KWin::Workspace::blockStackingUpdates(bool) () at /usr/lib64/libkwin.so.5
#10 0x00007fc4b4269c14 in KWin::Client::destroyClient() () at /usr/lib64/libkwin.so.5
#11 0x00007fc4b42cc339 in KWin::Client::unmapNotifyEvent(xcb_unmap_notify_event_t*) () at /usr/lib64/libkwin.so.5
#12 0x00007fc4b42cfb23 in KWin::Client::windowEvent(xcb_generic_event_t*) () at /usr/lib64/libkwin.so.5
#13 0x00007fc4b42d080e in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () at /usr/lib64/libkwin.so.5
#14 0x00007fc4b1d7feaf in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () at /usr/lib64/libQt5Core.so.5
#15 0x00007fc49ccfc960 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () at /usr/lib64/libQt5XcbQpa.so.5
#16 0x00007fc49ccfd5ac in QXcbConnection::processXcbEvents() () at /usr/lib64/libQt5XcbQpa.so.5
#17 0x00007fc4b1db0c42 in QObject::event(QEvent*) () at /usr/lib64/libQt5Core.so.5
#18 0x00007fc4b2b0793c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#19 0x00007fc4b2b0ecb4 in QApplication::notify(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#20 0x00007fc4b1d82d48 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib64/libQt5Core.so.5
#21 0x00007fc4b1d85335 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib64/libQt5Core.so.5
#22 0x00007fc4b1dd5a54 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#23 0x00007fc49cd5b06d in  () at /usr/lib64/libQt5XcbQpa.so.5
#24 0x00007fc4b1d8135a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#25 0x00007fc4b1d89be4 in QCoreApplication::exec() () at /usr/lib64/libQt5Core.so.5
#26 0x00007fc4b4a775a6 in kdemain () at /usr/lib64/libkdeinit5_kwin_x11.so
#27 0x00007fc4b46e846a in __libc_start_main (main=0xf89f196830, argc=3, argv=0x7ffc929c9a68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc929c9a58) at ../csu/libc-start.c:295
#28 0x000000f89f19686a in _start ()

Possible duplicates by query: bug 356616.

Reported using DrKonqi