Application: kwin_x11 (5.14.3)

Qt Version: 5.11.1
Frameworks Version: 5.52.0
Operating System: Linux 4.18.0-11-generic x86_64
Distribution: Ubuntu 18.10

-- Information about the crash:
- What I was doing when the application crashed:
Pressing Alt+Tab when we are working with many applications

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ce8507c0a4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
[Current thread is 1 (Thread 0x7f4227320840 (LWP 18465))]

Thread 6 (Thread 0x7f41ff7bf700 (LWP 18477)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f422fedafb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f422fedaf68, cond=0x7f422fedaf90) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f422fedaf90, mutex=0x7f422fedaf68) at pthread_cond_wait.c:655
#3  0x00007f422fde3e2a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#4  0x00007f422fde3e49 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#5  0x00007f422f0ee164 in start_thread (arg=<optimized out>) at pthread_create.c:486
#6  0x00007f423193adef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f4204ac4700 (LWP 18476)):
[KCrash Handler]
#6  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#7  0x00007f4231842535 in __GI_abort () at abort.c:79
#8  0x00007f423010a957 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x00007f4230110aa6 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#10 0x00007f4230110ae1 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x00007f42302b1d03 in qTerminate() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007f42302b40c6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007f422f0ee164 in start_thread (arg=<optimized out>) at pthread_create.c:486
#14 0x00007f423193adef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f421227e700 (LWP 18475)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ce84819638) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55ce848195e8, cond=0x55ce84819610) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55ce84819610, mutex=0x55ce848195e8) at pthread_cond_wait.c:655
#3  0x00007f42128dc46b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f42128dc1d7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f422f0ee164 in start_thread (arg=<optimized out>) at pthread_create.c:486
#6  0x00007f423193adef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f4225346700 (LWP 18471)):
#0  0x00007f423192e7d6 in __GI_ppoll (fds=0x7f421800eaf8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f42304ea141 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f42304eb5b9 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f423049b16b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f42302ea0b6 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f422e3f9545 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#6  0x00007f42302f3c87 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f422f0ee164 in start_thread (arg=<optimized out>) at pthread_create.c:486
#8  0x00007f423193adef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f42264f1700 (LWP 18469)):
#0  0x00007f423192e6d9 in __GI___poll (fds=0x7f42264f0c78, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f4230213917 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f423021553a in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f42269d8159 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007f42302f3c87 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f422f0ee164 in start_thread (arg=<optimized out>) at pthread_create.c:486
#6  0x00007f423193adef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f4227320840 (LWP 18465)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ce8507c0a4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55ce8507c050, cond=0x55ce8507c078) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55ce8507c078, mutex=0x55ce8507c050) at pthread_cond_wait.c:655
#3  0x00007f42302f443b in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f422e91e8b1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#5  0x00007f422e8bd025 in void QQmlTypeLoader::doLoad<PlainLoader>(PlainLoader const&, QQmlDataBlob*, QQmlTypeLoader::Mode) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f422e8abe66 in QQmlTypeLoader::load(QQmlDataBlob*, QQmlTypeLoader::Mode) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007f422e8ad968 in QQmlTypeLoader::getType(QUrl const&, QQmlTypeLoader::Mode) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f422e88a308 in QQmlComponentPrivate::loadUrl(QUrl const&, QQmlComponent::CompilationMode) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#9  0x00007f4231740f8b in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#10 0x00007f423174257a in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#11 0x00007f4231742769 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#12 0x00007f42304c56db in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007f42304d1407 in QTimer::timeout(QTimer::QPrivateSignal) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#14 0x00007f42304c5f4b in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007f4230e5d4a1 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007f4230e64ae0 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007f423049c499 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007f42304ed558 in QTimerInfoList::activateTimers() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007f42304eb70c in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#20 0x00007f4226a6a0ed in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#21 0x00007f423049b16b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f42304a32e2 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f4231a1447b in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#24 0x00007f423184409b in __libc_start_main (main=0x55ce83664050, argc=3, argv=0x7fff4bf22b68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff4bf22b58) at ../csu/libc-start.c:308
#25 0x000055ce8366408a in _start ()
[Inferior 1 (process 18465) detached]

Reported using DrKonqi