Application: kwin (4.11.22)
KDE Platform Version: 4.14.21
Qt Version: 4.8.7
Operating System: Linux 4.4.14 x86_64
Distribution (Platform): Slackware Packages

-- Information about the crash:
- What I was doing when the application crashed:
Trying to change my Desktop animation settings.
Re-enabling OpenGl is crashing the Kwin app.

-- Backtrace:
Application: KWin (kwin), signal: Aborted
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f6606a2a7c0 (LWP 1436))]

Thread 3 (Thread 0x7f65e5217700 (LWP 23019)):
#0  0x00007f6600977718 in pthread_cond_timedwait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f6600c128b2 in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib64/qt/lib/libQtCore.so.4
#2  0x00007f6600c05e7f in  () at /usr/lib64/qt/lib/libQtCore.so.4
#3  0x00007f6600c123bc in  () at /usr/lib64/qt/lib/libQtCore.so.4
#4  0x00007f6600971684 in start_thread () at /lib64/libpthread.so.0
#5  0x00007f65fea4cefd in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f65e6998700 (LWP 1443)):
#0  0x00007f660097736f in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f66059ee5aa in  () at /usr/lib64/qt/lib/libQtScript.so.4
#2  0x00007f66059ee5d9 in  () at /usr/lib64/qt/lib/libQtScript.so.4
#3  0x00007f6600971684 in start_thread () at /lib64/libpthread.so.0
#4  0x00007f65fea4cefd in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7f6606a2a7c0 (LWP 1436)):
[KCrash Handler]
#6  0x00007f65fe97b3f8 in raise () at /lib64/libc.so.6
#7  0x00007f65fe97cffa in abort () at /lib64/libc.so.6
#8  0x00007f65fe973c17 in __assert_fail_base () at /lib64/libc.so.6
#9  0x00007f65fe973cc2 in  () at /lib64/libc.so.6
#10 0x00007f6604be9d39 in  () at /usr/lib64/libX11.so.6
#11 0x00007f6604be9dce in  () at /usr/lib64/libX11.so.6
#12 0x00007f6604bea0ad in _XEventsQueued () at /usr/lib64/libX11.so.6
#13 0x00007f6604becd05 in _XGetRequest () at /usr/lib64/libX11.so.6
#14 0x00007f65ff7e9bd7 in  () at /usr/lib64/libGL.so.1
#15 0x00007f65ff7e9f27 in  () at /usr/lib64/libGL.so.1
#16 0x00007f655f251403 in  () at /usr/lib64/xorg/modules/dri/i965_dri.so
#17 0x00007f655f2518c1 in  () at /usr/lib64/xorg/modules/dri/i965_dri.so
#18 0x00007f655f2519ab in  () at /usr/lib64/xorg/modules/dri/i965_dri.so
#19 0x00007f655f202746 in  () at /usr/lib64/xorg/modules/dri/i965_dri.so
#20 0x00007f65ff7eb8ab in  () at /usr/lib64/libGL.so.1
#21 0x00007f65ff7c9007 in glXMakeCurrentReadSGI () at /usr/lib64/libGL.so.1
#22 0x00007f66065dbf5f in  () at /usr/lib64/libkdeinit4_kwin.so
#23 0x00007f66065dc490 in  () at /usr/lib64/libkdeinit4_kwin.so
#24 0x00007f66065d6ac4 in  () at /usr/lib64/libkdeinit4_kwin.so
#25 0x00007f66065b9a42 in  () at /usr/lib64/libkdeinit4_kwin.so
#26 0x00007f660653b825 in  () at /usr/lib64/libkdeinit4_kwin.so
#27 0x00007f6600d2ae30 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () at /usr/lib64/qt/lib/libQtCore.so.4
#28 0x00007f6600c02777 in QFutureWatcherBase::event(QEvent*) () at /usr/lib64/qt/lib/libQtCore.so.4
#29 0x00007f65ffe6d48c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib64/qt/lib/libQtGui.so.4
#30 0x00007f65ffe73f5c in QApplication::notify(QObject*, QEvent*) () at /usr/lib64/qt/lib/libQtGui.so.4
#31 0x00007f6601a3b8ea in KApplication::notify(QObject*, QEvent*) () at /usr/lib64/libkdeui.so.5
#32 0x00007f6600d17c0d in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /usr/lib64/qt/lib/libQtCore.so.4
#33 0x00007f6600d1ae6e in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib64/qt/lib/libQtCore.so.4
#34 0x00007f65fff11129 in  () at /usr/lib64/qt/lib/libQtGui.so.4
#35 0x00007f6600d165d1 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/qt/lib/libQtCore.so.4
#36 0x00007f6600d168e5 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/qt/lib/libQtCore.so.4
#37 0x00007f6600d1bec9 in QCoreApplication::exec() () at /usr/lib64/qt/lib/libQtCore.so.4
#38 0x00007f660656c826 in kdemain () at /usr/lib64/libkdeinit4_kwin.so
#39 0x00007f65fe9667d0 in __libc_start_main () at /lib64/libc.so.6
#40 0x0000000000400a09 in _start ()

Reported using DrKonqi