Application: kwin_x11 (5.12.7)

Qt Version: 5.9.5
Frameworks Version: 5.44.0
Operating System: Linux 4.15.0-52-generic x86_64
Distribution: Ubuntu 18.04.2 LTS

-- Information about the crash:
- What I was doing when the application crashed:
Basically as title said, when i move my mouse to the corner that shows all desktop windows, the kwin will crash. When it happened it appears that there is a significant CPU load (system a bit sluggish).

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 0x7fd08032dcc0 (LWP 1758))]

Thread 6 (Thread 0x7fd05efd0700 (LWP 6983)):
#0  0x00007fd07fc8bcf6 in __GI_ppoll (fds=0x7fd050001798, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007fd07d08d5c1 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fd07d08ecde in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd07d0369ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd07ce5522a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fd0777dd6f5 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007fd07ce5a16d in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fd078cf16db in start_thread (arg=0x7fd05efd0700) at pthread_create.c:463
#8  0x00007fd07fc9888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7fd046739700 (LWP 1896)):
#0  0x00007fd078cf79f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fd07c28efb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7fd07c28ef68, cond=0x7fd07c28ef90) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7fd07c28ef90, mutex=0x7fd07c28ef68) at pthread_cond_wait.c:655
#3  0x00007fd07bf985f4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#4  0x00007fd07bf98639 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#5  0x00007fd078cf16db in start_thread (arg=0x7fd046739700) at pthread_create.c:463
#6  0x00007fd07fc9888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7fd04d1ec700 (LWP 1891)):
#0  0x00007fd078cf79f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5654fdb06bb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x5654fdb06b68, cond=0x5654fdb06b90) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x5654fdb06b90, mutex=0x5654fdb06b68) at pthread_cond_wait.c:655
#3  0x00007fd04de8adcb in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007fd04de8aaf7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007fd078cf16db in start_thread (arg=0x7fd04d1ec700) at pthread_create.c:463
#6  0x00007fd07fc9888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fd05e370700 (LWP 1797)):
#0  __libc_disable_asynccancel () at ../sysdeps/unix/sysv/linux/x86_64/cancellation.S:98
#1  0x00007fd07fc8bd0a in __GI_ppoll (fds=<optimized out>, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#2  0x00007fd07d08d5c1 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd07d08ecde in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd07d0369ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fd07ce5522a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fd0777dd6f5 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007fd07ce5a16d in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fd078cf16db in start_thread (arg=0x7fd05e370700) at pthread_create.c:463
#9  0x00007fd07fc9888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fd05ffff700 (LWP 1792)):
#0  0x00007fd07fc8bcf6 in __GI_ppoll (fds=0x7fd05800b378, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007fd07d08d5c1 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fd07d08ecde in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd07d0369ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd07ce5522a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fd0766b6d45 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#6  0x00007fd07ce5a16d in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fd078cf16db in start_thread (arg=0x7fd05ffff700) at pthread_create.c:463
#8  0x00007fd07fc9888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fd08032dcc0 (LWP 1758)):
[KCrash Handler]
#6  0x00005654fe1c00c0 in ?? ()
#7  0x00007fd07f7933aa in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#8  0x00007fd07d03558f in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fd067889820 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#10 0x00007fd06788a4ac in QXcbConnection::processXcbEvents() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#11 0x00007fd07d068122 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fd07ddb682c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#13 0x00007fd07ddbe0f4 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fd07d0389a8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007fd07d03b11d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fd07d08eaf4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007fd0678eb5cd in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#18 0x00007fd07d0369ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007fd07d03fa84 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#20 0x00007fd07ff70dbb in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#21 0x00007fd07fb98b97 in __libc_start_main (main=0x5654fcd4c730, argc=1, argv=0x7ffea7bb9158, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffea7bb9148) at ../csu/libc-start.c:310
#22 0x00005654fcd4c76a in _start ()

The reporter indicates this bug may be a duplicate of or related to bug 405829, bug 404884, bug 402769.

Possible duplicates by query: bug 409815, bug 409715, bug 409223, bug 406784, bug 406391.

Reported using DrKonqi