Application: kwin_x11 (5.12.7)

Qt Version: 5.9.5
Frameworks Version: 5.47.0
Operating System: Linux 4.15.0-24-generic x86_64
Distribution: Ubuntu 18.04.2 LTS

-- Information about the crash:
chiusura inaspettata kwin

The crash can be reproduced sometimes.

-- 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 0x7f1628aa8cc0 (LWP 16310))]

Thread 6 (Thread 0x7f15e5738700 (LWP 16324)):
#0  0x00007f16214659f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f1624a07fb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f16214659f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x7f1624a07f68, cond=0x7f1624a07f90) at pthread_cond_wait.c:502
#2  0x00007f16214659f3 in __pthread_cond_wait (cond=0x7f1624a07f90, mutex=0x7f1624a07f68) at pthread_cond_wait.c:655
#3  0x00007f16247115f4 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#4  0x00007f1624711639 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#5  0x00007f162145f6db in start_thread (arg=0x7f15e5738700) at pthread_create.c:463
#6  0x00007f162841288f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f15ed369700 (LWP 16321)):
#0  0x00007f1628405cf6 in __GI_ppoll (fds=0x7f15e0000d28, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f1625806671 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f1625807d8e in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f16257afa1a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f16255ce23a in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f161ff4b6f5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f16255d317d in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f162145f6db in start_thread (arg=0x7f15ed369700) at pthread_create.c:463
#8  0x00007f162841288f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f15f02cc700 (LWP 16319)):
#0  0x00007f16214659f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ba11c36a88) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f16214659f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x55ba11c36a38, cond=0x55ba11c36a60) at pthread_cond_wait.c:502
#2  0x00007f16214659f3 in __pthread_cond_wait (cond=0x55ba11c36a60, mutex=0x55ba11c36a38) at pthread_cond_wait.c:655
#3  0x00007f15f0f6adcb in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f15f0f6aaf7 in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f162145f6db in start_thread (arg=0x7f15f02cc700) at pthread_create.c:463
#6  0x00007f162841288f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f15f9b78700 (LWP 16318)):
#0  0x00007f1628405cf6 in __GI_ppoll (fds=0x7f15f4000d28, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f1625806671 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f1625807d8e in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f16257afa1a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f16255ce23a in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f161ff4b6f5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f16255d317d in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f162145f6db in start_thread (arg=0x7f15f9b78700) at pthread_create.c:463
#8  0x00007f162841288f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f160cab1700 (LWP 16314)):
#0  0x00007f1628405cf6 in __GI_ppoll (fds=0x7f160000e628, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f1625806671 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f1625807d8e in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f16257afa1a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f16255ce23a in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f161ee1bd45 in  () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#6  0x00007f16255d317d in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f162145f6db in start_thread (arg=0x7f160cab1700) at pthread_create.c:463
#8  0x00007f162841288f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f1628aa8cc0 (LWP 16310)):
[KCrash Handler]
#6  0x000055ba130bb148 in  ()
#7  0x00007f1627ecbda8 in  () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#8  0x00007f1627ecc110 in  () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#9  0x00007f1627f27fd3 in KWin::Workspace::activateNextClient(KWin::AbstractClient*) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#10 0x00007f1627eab4dc in KWin::Client::releaseWindow(bool) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#11 0x00007f1627f097ea in KWin::Client::unmapNotifyEvent(xcb_unmap_notify_event_t*) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#12 0x00007f1627f0ce6b in KWin::Client::windowEvent(xcb_generic_event_t*) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#13 0x00007f1627f0d7f5 in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5
#14 0x00007f16257ae5bf in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007f160ffee820 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#16 0x00007f160ffef4ac in QXcbConnection::processXcbEvents() () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#17 0x00007f16257e11d2 in QObject::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007f162652f83c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#19 0x00007f1626537104 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#20 0x00007f16257b19e8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#21 0x00007f16257b415d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f1625807ba4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f16100505cd in  () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#24 0x00007f16257afa1a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007f16257b8ac4 in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007f16286eadbb in kdemain () at /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#27 0x00007f1628312b97 in __libc_start_main (main=0x55ba0f963730, argc=3, argv=0x7fff866455f8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff866455e8) at ../csu/libc-start.c:310
#28 0x000055ba0f96376a in _start ()

Reported using DrKonqi