Application: kwin_x11 (5.4.3)

Qt Version: 5.5.1
Operating System: Linux 4.2.6-300.fc23.x86_64 x86_64
Distribution: "Fedora release 23 (Twenty Three)"

-- Information about the crash:
I wastrying to enable 3 displays with my X1 - and setting up the middle screen as the main screen. 
usually when I'm changin the diplays config - kwin is crashin.

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f8b13cee940 (LWP 2270))]

Thread 3 (Thread 0x7f8aeadee700 (LWP 2362)):
#0  0x00007f8b08e9dd63 in select () at /lib64/libc.so.6
#1  0x00007f8b0a3fa57f in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () at /lib64/libQt5Core.so.5
#2  0x00007f8b0a3fc07e in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () at /lib64/libQt5Core.so.5
#3  0x00007f8b0a3fc5ae in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f8b0a3a5f0a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#5  0x00007f8b0a1c2424 in QThread::exec() () at /lib64/libQt5Core.so.5
#6  0x00007f8b114dcb45 in QQmlThreadPrivate::run() () at /lib64/libQt5Qml.so.5
#7  0x00007f8b0a1c73ce in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#8  0x00007f8b0c79160a in start_thread () at /lib64/libpthread.so.0
#9  0x00007f8b08ea7a7d in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f8ae307a700 (LWP 2411)):
#0  0x00007f8b0c796b10 in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f8b12af0514 in QTWTF::TCMalloc_PageHeap::scavengerThread() () at /lib64/libQt5Script.so.5
#2  0x00007f8b12af0559 in  () at /lib64/libQt5Script.so.5
#3  0x00007f8b0c79160a in start_thread () at /lib64/libpthread.so.0
#4  0x00007f8b08ea7a7d in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7f8b13cee940 (LWP 2270)):
[KCrash Handler]
#5  0x00007f8af2c6b55c in QXcbScreen::mapFromNative(QPoint const&) const () at /lib64/libQt5XcbQpa.so.5
#6  0x00007f8af2c739aa in QXcbWindow::handleEnterNotifyEvent(xcb_enter_notify_event_t const*) () at /lib64/libQt5XcbQpa.so.5
#7  0x00007f8af2c5cafd in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () at /lib64/libQt5XcbQpa.so.5
#8  0x00007f8af2c5d433 in QXcbConnection::processXcbEvents() () at /lib64/libQt5XcbQpa.so.5
#9  0x00007f8b0a3d81b1 in QObject::event(QEvent*) () at /lib64/libQt5Core.so.5
#10 0x00007f8b0b08e41c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#11 0x00007f8b0b0938e6 in QApplication::notify(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#12 0x00007f8b0a3a877b in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#13 0x00007f8b0a3aab76 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /lib64/libQt5Core.so.5
#14 0x00007f8b0a3fc472 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#15 0x00007f8af2cc195d in QUnixEventDispatcherQPA::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5XcbQpa.so.5
#16 0x00007f8b0a3a5f0a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#17 0x00007f8b0a3adfec in QCoreApplication::exec() () at /lib64/libQt5Core.so.5
#18 0x00007f8b139efb93 in kdemain () at /lib64/libkdeinit5_kwin_x11.so
#19 0x00007f8b08dc5580 in __libc_start_main () at /lib64/libc.so.6
#20 0x0000564188dc3d89 in _start ()

Possible duplicates by query: bug 355585.

Reported using DrKonqi