Application: kdenlive (18.07.70)
 (Compiled from sources)
Qt Version: 5.10.0
Frameworks Version: 5.46.0
Operating System: Linux 4.16.6-1-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
One or two seconds after adding the "OpenCV face blur effect" kdenlive crashes with the attached backtrace.

I happens with all the clips I have tried.

If needed for debugging,  I can recompile pretty much everything.

Right now I am using:
-MLT compiled from sources, v6.6.0
-KDenlive compiled from sources (master)
-OpenCV 3.4.1-2

Thanks for all the great work :)

The crash can be reproduced every time.

-- Backtrace:
Application: Kdenlive (kdenlive), signal: Aborted
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f8cf7dd4840 (LWP 10216))]

Thread 33 (Thread 0x7f8c30ffa700 (LWP 10311)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ca9cff73d in video_thread (arg=0x56236f461ee0) at ../sdl/consumer_sdl_audio.c:420
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 32 (Thread 0x7f8c31ffc700 (LWP 10309)):
#0  0x00007f8ce3f57626 in  () at /usr/lib/pulseaudio/libpulsecommon-11.1.so
#1  0x00007f8ce3f58850 in  () at /usr/lib/pulseaudio/libpulsecommon-11.1.so
#2  0x00007f8ce3f58b8a in  () at /usr/lib/pulseaudio/libpulsecommon-11.1.so
#3  0x00007f8ce3f59440 in  () at /usr/lib/pulseaudio/libpulsecommon-11.1.so
#4  0x00007f8ce60f8ea8 in pa_mainloop_dispatch () at /usr/lib/libpulse.so.0
#5  0x00007f8ce60f9280 in pa_mainloop_iterate () at /usr/lib/libpulse.so.0
#6  0x00007f8cc51672e7 in  () at /usr/lib/libSDL2-2.0.so.0
#7  0x00007f8cc50c2dc3 in  () at /usr/lib/libSDL2-2.0.so.0
#8  0x00007f8cc510881f in  () at /usr/lib/libSDL2-2.0.so.0
#9  0x00007f8cc518838a in  () at /usr/lib/libSDL2-2.0.so.0
#10 0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 31 (Thread 0x7f8c3effd700 (LWP 10308)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 30 (Thread 0x7f8c3f7fe700 (LWP 10307)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 29 (Thread 0x7f8c3ffff700 (LWP 10306)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 28 (Thread 0x7f8c617fa700 (LWP 10305)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 27 (Thread 0x7f8c7de79700 (LWP 10304)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 26 (Thread 0x7f8c9ca1a700 (LWP 10302)):
[KCrash Handler]
#6  0x00007f8cedd7786b in raise () at /usr/lib/libc.so.6
#7  0x00007f8cedd6240e in abort () at /usr/lib/libc.so.6
#8  0x00007f8cee73344a in __gnu_cxx::__verbose_terminate_handler() () at /build/gcc/src/gcc/libstdc++-v3/libsupc++/vterminate.cc:95
#9  0x00007f8cee7399d6 in __cxxabiv1::__terminate(void (*)()) (handler=<optimized out>) at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:47
#10 0x00007f8cee739a13 in std::terminate() () at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:57
#11 0x00007f8ceeac9cc9 in qTerminate() () at /home/afiestas/Projects/qt5/qtbase/src/corelib/global/qglobal.cpp:3114
#12 0x00007f8ceeae4b1e in QThreadPrivate::start(void*) (arg=0x7f8c5c00b650) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:388
#13 0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#14 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 25 (Thread 0x7f8c61ffb700 (LWP 10301)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cf6a5f9cb in mlt_consumer_rt_frame (self=self@entry=0x56236f461ee0) at mlt_consumer.c:1577
#2  0x00007f8ca9cff093 in consumer_thread (arg=0x56236f461ee0) at ../sdl/consumer_sdl_audio.c:528
#3  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 24 (Thread 0x7f8ca4072700 (LWP 10300)):
#0  0x00007f8cede2a934 in read () at /usr/lib/libc.so.6
#1  0x00007f8ce3f397c2 in pa_read () at /usr/lib/pulseaudio/libpulsecommon-11.1.so
#2  0x00007f8ce60f87af in pa_mainloop_prepare () at /usr/lib/libpulse.so.0
#3  0x00007f8ce60f9241 in pa_mainloop_iterate () at /usr/lib/libpulse.so.0
#4  0x00007f8ce60f9301 in pa_mainloop_run () at /usr/lib/libpulse.so.0
#5  0x00007f8cc5167450 in  () at /usr/lib/libSDL2-2.0.so.0
#6  0x00007f8cc510881f in  () at /usr/lib/libSDL2-2.0.so.0
#7  0x00007f8cc518838a in  () at /usr/lib/libSDL2-2.0.so.0
#8  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 23 (Thread 0x7f8bf91a5700 (LWP 10296)):
#0  0x00007f8cede2a934 in read () at /usr/lib/libc.so.6
#1  0x00007f8ce63b6ed1 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f8ce6370ff8 in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ce63714c6 in  () at /usr/lib/libglib-2.0.so.0
#4  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#5  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8bcc003070, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8bf91a4d60, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#7  0x00007f8ceeadf7fa in QThread::exec() (this=<optimized out>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#8  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x7f8cd80452e0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#9  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#10 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 22 (Thread 0x7f8c4c931700 (LWP 10259)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 21 (Thread 0x7f8c4d132700 (LWP 10258)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 20 (Thread 0x7f8c4d933700 (LWP 10257)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 19 (Thread 0x7f8c4e134700 (LWP 10256)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 18 (Thread 0x7f8c60ff9700 (LWP 10255)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 17 (Thread 0x7f8c627fc700 (LWP 10248)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cf6a6768b in mlt_slices_worker (p=0x7f8c5c1a01b0) at mlt_slices.c:95
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 16 (Thread 0x7f8c62ffd700 (LWP 10247)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cf6a6768b in mlt_slices_worker (p=0x7f8c5c1a01b0) at mlt_slices.c:95
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 15 (Thread 0x7f8c637fe700 (LWP 10246)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cf6a6768b in mlt_slices_worker (p=0x7f8c5c1a01b0) at mlt_slices.c:95
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 14 (Thread 0x7f8c63fff700 (LWP 10245)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cf6a6768b in mlt_slices_worker (p=0x7f8c5c1a01b0) at mlt_slices.c:95
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 13 (Thread 0x7f8c70a2c700 (LWP 10244)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 12 (Thread 0x7f8c7122d700 (LWP 10243)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 11 (Thread 0x7f8c71a2e700 (LWP 10242)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 10 (Thread 0x7f8c7222f700 (LWP 10241)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 9 (Thread 0x7f8c9da1c700 (LWP 10240)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8ccb7be62f in  () at /usr/lib/libavcodec.so.57
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 8 (Thread 0x7f8c7e67a700 (LWP 10235)):
#0  0x00007f8cede2eea9 in poll () at /usr/lib/libc.so.6
#1  0x00007f8ce6371523 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8c58000b20, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8c7e679d60, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#5  0x00007f8ceeadf7fa in QThread::exec() (this=<optimized out>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#6  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x562371e9afc0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#7  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 7 (Thread 0x7f8c9d21b700 (LWP 10233)):
#0  0x00007f8cede2eea9 in poll () at /usr/lib/libc.so.6
#1  0x00007f8ce6371523 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8c74000b20, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8c9d21ad60, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#5  0x00007f8ceeadf7fa in QThread::exec() (this=<optimized out>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#6  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x562371e58380) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#7  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 6 (Thread 0x7f8c9f7fe700 (LWP 10226)):
#0  0x00007f8cede2a934 in read () at /usr/lib/libc.so.6
#1  0x00007f8ce63b6ed1 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f8ce6370ff8 in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ce63714c6 in  () at /usr/lib/libglib-2.0.so.0
#4  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#5  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8c90000b20, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8c9f7fdd40, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#7  0x00007f8ceeadf7fa in QThread::exec() (this=this@entry=0x56236e6d81a0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#8  0x00007f8ceff64745 in QQmlThreadPrivate::run() (this=0x56236e6d81a0) at /home/afiestas/Projects/qt5/qtdeclarative/src/qml/qml/ftw/qqmlthread.cpp:147
#9  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x56236e6d81a0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#10 0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 5 (Thread 0x7f8ca576d700 (LWP 10220)):
#0  0x00007f8cede2a934 in read () at /usr/lib/libc.so.6
#1  0x00007f8ce63b6ed1 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f8ce6370ff8 in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ce63714c6 in  () at /usr/lib/libglib-2.0.so.0
#4  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#5  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8ca0000b20, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8ca576cd40, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#7  0x00007f8ceeadf7fa in QThread::exec() (this=this@entry=0x56236f03ac80) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#8  0x00007f8ceff64745 in QQmlThreadPrivate::run() (this=0x56236f03ac80) at /home/afiestas/Projects/qt5/qtdeclarative/src/qml/qml/ftw/qqmlthread.cpp:147
#9  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x56236f03ac80) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#10 0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7f8cad9c0700 (LWP 10219)):
#0  0x00007f8cede2eea9 in poll () at /usr/lib/libc.so.6
#1  0x00007f8cb03b8c90 in  () at /usr/lib/libusb-1.0.so.0
#2  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#3  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7f8cd639f700 (LWP 10218)):
#0  0x00007f8cede46884 in __libc_enable_asynccancel () at /usr/lib/libc.so.6
#1  0x00007f8cede2a925 in read () at /usr/lib/libc.so.6
#2  0x00007f8ce63b6ed1 in  () at /usr/lib/libglib-2.0.so.0
#3  0x00007f8ce6370ff8 in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#4  0x00007f8ce63714c6 in  () at /usr/lib/libglib-2.0.so.0
#5  0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#6  0x00007f8ceed25cab in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f8cd0000b20, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:425
#7  0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f8cd639ed30, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#8  0x00007f8ceeadf7fa in QThread::exec() (this=this@entry=0x7f8cf0f04d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread.cpp:522
#9  0x00007f8cf0c924f5 in QDBusConnectionManager::run() (this=0x7f8cf0f04d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at /home/afiestas/Projects/qt5/qtbase/src/dbus/qdbusconnection.cpp:178
#10 0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x7f8cf0f04d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#11 0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#12 0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7f8ce01b9700 (LWP 10217)):
#0  0x00007f8cede2eea9 in poll () at /usr/lib/libc.so.6
#1  0x00007f8cea9c7180 in  () at /usr/lib/libxcb.so.1
#2  0x00007f8cea9c8e4b in xcb_wait_for_event () at /usr/lib/libxcb.so.1
#3  0x00007f8ce2521389 in QXcbEventReader::run() (this=0x56236d6d67c0) at /home/afiestas/Projects/qt5/qtbase/src/plugins/platforms/xcb/qxcbconnection.cpp:1371
#4  0x00007f8ceeae49cf in QThreadPrivate::start(void*) (arg=0x56236d6d67c0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/thread/qthread_unix.cpp:376
#5  0x00007f8cec1a1075 in start_thread () at /usr/lib/libpthread.so.0
#6  0x00007f8cede3953f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7f8cf7dd4840 (LWP 10216)):
#0  0x00007f8cec1a6ffc in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f8cea9c7393 in  () at /usr/lib/libxcb.so.1
#2  0x00007f8cea9c8b3f in  () at /usr/lib/libxcb.so.1
#3  0x00007f8cea9c8c51 in xcb_wait_for_reply () at /usr/lib/libxcb.so.1
#4  0x00007f8ce252026a in QXcbConnection::sync() (this=0x56236d6c9780) at /home/afiestas/Projects/qt5/qtbase/src/plugins/platforms/xcb/qxcbconnection.cpp:2081
#5  0x00007f8ce25424d3 in QXcbShmImage::preparePaint(QRegion const&) (this=0x56237206cca0, region=...) at /home/afiestas/Projects/qt5/qtbase/src/plugins/platforms/xcb/qxcbbackingstore.cpp:489
#6  0x00007f8ce25425ac in QXcbBackingStore::beginPaint(QRegion const&) (this=this@entry=0x56236ea5f4b0, region=...) at /home/afiestas/Projects/qt5/qtbase/src/plugins/platforms/xcb/qxcbbackingstore.cpp:523
#7  0x00007f8cef3d9dab in QBackingStore::beginPaint(QRegion const&) (this=this@entry=0x56236ef5c640, region=...) at /home/afiestas/Projects/qt5/qtbase/src/gui/painting/qbackingstore.cpp:134
#8  0x00007f8cf1074984 in QWidgetBackingStore::beginPaint(QRegion&, QWidget*, QBackingStore*, BeginPaintInfo*, bool) (toCleanIsInTopLevelCoordinates=true, returnInfo=<synthetic pointer>, backingStore=0x56236ef5c640, widget=<optimized out>, toClean=..., this=0x56236ead9f60) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp:327
#9  0x00007f8cf1074984 in QWidgetBackingStore::doSync() (this=this@entry=0x56236ead9f60) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp:1335
#10 0x00007f8cf1074e15 in QWidgetBackingStore::sync() (this=0x56236ead9f60) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp:1156
#11 0x00007f8cf108c4af in QWidgetPrivate::syncBackingStore() (this=0x56236dce67e0) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qwidget.cpp:1959
#12 0x00007f8cf10a4548 in QWidget::event(QEvent*) (this=this@entry=0x56236dce6420, event=event@entry=0x5623746987b0) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qwidget.cpp:9137
#13 0x00007f8cf11b7dd0 in QMainWindow::event(QEvent*) (this=0x56236dce6420, event=0x5623746987b0) at /home/afiestas/Projects/qt5/qtbase/src/widgets/widgets/qmainwindow.cpp:1342
#14 0x00007f8cf41230da in KMainWindow::event(QEvent*) (this=0x56236dce6420, ev=0x5623746987b0) at /home/afiestas/Projects/kde5/source/kxmlgui/src/kmainwindow.cpp:865
#15 0x00007f8cf4168a7f in KXmlGuiWindow::event(QEvent*) (this=0x56236dce6420, ev=0x5623746987b0) at /home/afiestas/Projects/kde5/source/kxmlgui/src/kxmlguiwindow.cpp:119
#16 0x00007f8cf106570c in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=0x56236d6ba040, receiver=receiver@entry=0x56236dce6420, e=e@entry=0x5623746987b0) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3732
#17 0x00007f8cf106ce94 in QApplication::notify(QObject*, QEvent*) (this=0x7fff3796eab0, receiver=0x56236dce6420, e=0x5623746987b0) at /home/afiestas/Projects/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3491
#18 0x00007f8ceeccb128 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x56236dce6420, event=event@entry=0x5623746987b0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1042
#19 0x00007f8ceeccdcbd in QCoreApplication::sendEvent(QObject*, QEvent*) (event=0x5623746987b0, receiver=<optimized out>) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qcoreapplication.h:234
#20 0x00007f8ceeccdcbd in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x56236d6b85a0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1717
#21 0x00007f8ceecce248 in QCoreApplication::sendPostedEvents(QObject*, int) (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1571
#22 0x00007f8ceed26663 in postEventSourceDispatch(GSource*, GSourceFunc, gpointer) (s=0x56236d701870) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:276
#23 0x00007f8ce6371368 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#24 0x00007f8ce63715b1 in  () at /usr/lib/libglib-2.0.so.0
#25 0x00007f8ce637163e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#26 0x00007f8ceed25c8f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x56236d703610, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:423
#27 0x00007f8ce25a6631 in QPAEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x56236d703610, flags=...) at /home/afiestas/Projects/qt5/qtbase/src/platformsupport/eventdispatchers/qeventdispatcher_glib.cpp:69
#28 0x00007f8ceecc980a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fff3796e9a0, flags=..., flags@entry=...) at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:212
#29 0x00007f8ceecd27d4 in QCoreApplication::exec() () at /home/afiestas/Projects/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1330
#30 0x000056236b7a5a81 in main(int, char**) (argc=<optimized out>, argv=<optimized out>) at /home/afiestas/Projects/kde5/source/kdenlive/src/main.cpp:164

Possible duplicates by query: bug 389500, bug 382439.

Reported using DrKonqi