Application: kontact (5.10.1)

Qt Version: 5.12.0
Frameworks Version: 5.55.0
Operating System: Linux 4.15.0-45-generic x86_64
Distribution: KDE neon User Edition 5.15

-- Information about the crash:
I'm going back to thunderbird. Despite KMail definitively being the better mail app.

Sorry, gals 'n' guys.
I went from Ubuntu to KDE Neon because I found KDE is by far the better desktop experience now that Unity is going (I liked Unity).
I tried Kontact/KDE and was surprised what features it had compared to my Thunderbird/Lightning/SOGO setup with Caldav and Carddav.

It worked great at first, maybe except for the weak HTML support in the mail editor (especially when replying).

Then KMail started stalling when fetching mail, mostly after resuming from sleep mode, or when cleaning up inboxes with a lot of moving and deleting email.
Some research pointed me to the Akonadi framework running in the background, and a ~2GB MySQL database in .local/share/akonadi acting as "cache" for all my mails.

And this "cache" kept breaking on me. "akonadictl restart" on the console spew thousands of "multiple merge candidates" and "lock time exceeded" errors, which appeared again and again regardless how often I deleted my whole KDE setup and configured everything from scratch.

Thunderbird is clunkier, not as nice, not as fast.
But it *works*.
I have never lost email. It can find the right email quickly with the global search feature and "drill down" options.
Whatever local database it has, it doesn't break on me and doesn't create duplicate or missing emails.

Please close this bug only after Akonadi has been made either significantly more robust or replaced by something more robust.

I will stay with KDE, and I will keep my Akonadi configuration, so if there are follow-up questions, I'm happy to answer and do some research to help fix this.

The crash can be reproduced every time.

-- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f766c4f7080 (LWP 9566))]

Thread 29 (Thread 0x7f74e2b92700 (LWP 16169)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f74e2b91750, expected=0, futex_word=0x7f74e2b91938) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f74e2b917f0, mutex=0x7f74e2b918e8, cond=0x7f74e2b91910) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f74e2b91910, mutex=0x7f74e2b918e8, abstime=0x7f74e2b917f0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74bc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32851 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f35387 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f35974 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f74e2b92700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 28 (Thread 0x7f74e4395700 (LWP 16168)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f74e4394750, expected=0, futex_word=0x7f74e4394938) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f74e43947f0, mutex=0x7f74e43948e8, cond=0x7f74e4394910) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f74e4394910, mutex=0x7f74e43948e8, abstime=0x7f74e43947f0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74bc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32851 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f356b6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f35974 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f74e4395700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 27 (Thread 0x7f74f74e9700 (LWP 16167)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f74f74e8750, expected=0, futex_word=0x7f74f74e8938) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f74f74e87f0, mutex=0x7f74f74e88e8, cond=0x7f74f74e8910) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f74f74e8910, mutex=0x7f74f74e88e8, abstime=0x7f74f74e87f0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74bc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32851 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f35387 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f35974 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f74f74e9700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 26 (Thread 0x7f74f7cea700 (LWP 15458)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f74f7ce9750, expected=0, futex_word=0x7f74f7ce9938) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f74f7ce97f0, mutex=0x7f74f7ce98e8, cond=0x7f74f7ce9910) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f74f7ce9910, mutex=0x7f74f7ce98e8, abstime=0x7f74f7ce97f0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74bc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32851 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f356b6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f35974 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f74f7cea700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 25 (Thread 0x7f751ac4c700 (LWP 15233)):
#0  0x00007f7668e09bf9 in __GI___poll (fds=0x7f75440027c0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f7662841539 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766470d6db in start_thread (arg=0x7f751ac4c700) at pthread_create.c:463
#8  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 24 (Thread 0x7f74f2ce8700 (LWP 11260)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=123, buf=0x7f74f2ce785e, nbytes=10) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f761459dff1 in pa_read () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-11.1.so
#2  0x00007f76280a99fe in pa_mainloop_prepare () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#3  0x00007f76280aa470 in pa_mainloop_iterate () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#4  0x00007f76280aa530 in pa_mainloop_run () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#5  0x00007f76280b8399 in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#6  0x00007f76145cd2a8 in ?? () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-11.1.so
#7  0x00007f766470d6db in start_thread (arg=0x7f74f2ce8700) at pthread_create.c:463
#8  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 23 (Thread 0x7f76167fc700 (LWP 9946)):
#0  0x00007f7662887049 in g_mutex_lock () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f7662840aa3 in g_main_context_prepare () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f766284146b in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766470d6db in start_thread (arg=0x7f76167fc700) at pthread_create.c:463
#9  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 22 (Thread 0x7f75133c7700 (LWP 9644)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=101, buf=0x7f75133c6810, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f7662885cd0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7662841027 in g_main_context_check () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f76628414e0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f766470d6db in start_thread (arg=0x7f75133c7700) at pthread_create.c:463
#10 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 21 (Thread 0x7f7525c51700 (LWP 9617)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=84, buf=0x7f7525c50810, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f7662885cd0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7662841027 in g_main_context_check () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f76628414e0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f766470d6db in start_thread (arg=0x7f7525c51700) at pthread_create.c:463
#10 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 20 (Thread 0x7f752f3a1700 (LWP 9609)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=77, buf=0x7f752f3a0810, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f7662885cd0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7662841027 in g_main_context_check () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f76628414e0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f766470d6db in start_thread (arg=0x7f752f3a1700) at pthread_create.c:463
#10 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 19 (Thread 0x7f752fba2700 (LWP 9608)):
#0  0x00007f7662887049 in g_mutex_lock () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f7662840c81 in g_main_context_query () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f76628414b7 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766470d6db in start_thread (arg=0x7f752fba2700) at pthread_create.c:463
#9  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 18 (Thread 0x7f7534bd2700 (LWP 9607)):
#0  0x00007f7668e09bf9 in __GI___poll (fds=0x7f7530004a10, nfds=1, timeout=10242) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f7662841539 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766470d6db in start_thread (arg=0x7f7534bd2700) at pthread_create.c:463
#8  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 17 (Thread 0x7f754affd700 (LWP 9594)):
#0  0x00007f76647139f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f754affc948) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f754affc8f8, cond=0x7f754affc920) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f754affc920, mutex=0x7f754affc8f8) at pthread_cond_wait.c:655
#3  0x00007f7659f740a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ae8 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74b7f in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32868 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f356b6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f359f4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f754affd700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 16 (Thread 0x7f754b7fe700 (LWP 9593)):
#0  0x00007f7668d509d3 in _IO_vfprintf_internal (s=s@entry=0x7f754b7fd0b0, format=format@entry=0x7f765157eaed ": %s", ap=ap@entry=0x7f754b7fd250) at vfprintf.c:1676
#1  0x00007f7668e27169 in ___vsnprintf_chk (s=0x7f754b7fd33a ": Ung\303\274ltiger Dateideskriptor", maxlen=<optimized out>, flags=1, slen=<optimized out>, format=0x7f765157eaed ": %s", args=0x7f754b7fd250) at vsnprintf_chk.c:63
#2  0x00007f76515603b3 in evutil_vsnprintf () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#3  0x00007f765156044f in evutil_snprintf () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#4  0x00007f765156395c in event_logv_ () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#5  0x00007f7651563b44 in event_warn () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#6  0x00007f765156546c in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#7  0x00007f765155b114 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#8  0x00007f7659f7a8c4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f7659f43d21 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#11 0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#12 0x00007f766470d6db in start_thread (arg=0x7f754b7fe700) at pthread_create.c:463
#13 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 15 (Thread 0x7f75f1970700 (LWP 9591)):
#0  0x00007f76647139f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f7652ca1fb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f7652ca1f68, cond=0x7f7652ca1f90) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f7652ca1f90, mutex=0x7f7652ca1f68) at pthread_cond_wait.c:655
#3  0x00007f76529ab844 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#4  0x00007f76529ab889 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#5  0x00007f766470d6db in start_thread (arg=0x7f75f1970700) at pthread_create.c:463
#6  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 14 (Thread 0x7f75f2171700 (LWP 9590)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=48, buf=0x7f75f217085e, nbytes=10) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f761459dff1 in pa_read () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-11.1.so
#2  0x00007f76280a99fe in pa_mainloop_prepare () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#3  0x00007f76280aa470 in pa_mainloop_iterate () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#4  0x00007f76280aa530 in pa_mainloop_run () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#5  0x00007f76280b8399 in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#6  0x00007f76145cd2a8 in ?? () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-11.1.so
#7  0x00007f766470d6db in start_thread (arg=0x7f75f2171700) at pthread_create.c:463
#8  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 13 (Thread 0x7f75f2ffd700 (LWP 9589)):
#0  __lll_lock_wait_private () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95
#1  0x00007f7668e27474 in ___fprintf_chk (fp=0x7f76690e28b0 <_IO_stdfile_2_lock>, flag=1, format=0x7f765157b6a8 "[%s] %s\n") at fprintf_chk.c:30
#2  0x00007f76515639ad in event_logv_ () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#3  0x00007f7651563b44 in event_warn () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#4  0x00007f765156546c in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#5  0x00007f765155b114 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#6  0x00007f7659f7a789 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f43d21 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f75f2ffd700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 12 (Thread 0x7f75f37fe700 (LWP 9588)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=5, buf=0x7f75f37fc1b8, nbytes=984) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f765a1dbda0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#2  0x00007f765a1dc528 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#3  0x00007f765a1dca55 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f690f5 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f6a447 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659ee3512 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659ee582e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659ed99c9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f76589a0333 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f765c769dd5 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#11 0x00007f765c769df1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#12 0x00007f765c772fda in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#13 0x00007f765c773463 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#14 0x00007f765c77e701 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#15 0x00007f765c77a54f in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#16 0x00007f765c77a711 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#17 0x00007f765c77aa6b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#18 0x00007f765c77b085 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#19 0x00007f7659ece133 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#20 0x00007f7659ef3c2a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#21 0x00007f7659ef42ef in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#22 0x00007f7659ef4478 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#23 0x00007f7659eeeb11 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#24 0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#25 0x00007f7659f43d21 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#26 0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#27 0x00007f766470d6db in start_thread (arg=0x7f75f37fe700) at pthread_create.c:463
#28 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 11 (Thread 0x7f75f3fff700 (LWP 9587)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f75f3ffe740, expected=0, futex_word=0x7f75f3ffe928) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f75f3ffe7e0, mutex=0x7f75f3ffe8d8, cond=0x7f75f3ffe900) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f75f3ffe900, mutex=0x7f75f3ffe8d8, abstime=0x7f75f3ffe7e0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659eeeb70 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f43d21 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f766470d6db in start_thread (arg=0x7f75f3fff700) at pthread_create.c:463
#10 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x7f7614ff9700 (LWP 9586)):
#0  0x00007f76647139f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f7604003698) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f76040035d8, cond=0x7f7604003670) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f7604003670, mutex=0x7f76040035d8) at pthread_cond_wait.c:655
#3  0x00007f7659f740a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f765a83db28 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f452df in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f766470d6db in start_thread (arg=0x7f7614ff9700) at pthread_create.c:463
#8  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f76157fa700 (LWP 9585)):
#0  0x00007f76647139f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f76157f9948) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f76157f98f8, cond=0x7f76157f9920) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f76157f9920, mutex=0x7f76157f98f8) at pthread_cond_wait.c:655
#3  0x00007f7659f740a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ae8 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74b7f in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32868 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f356b6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f359b4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f76157fa700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f76177fe700 (LWP 9581)):
#0  0x00007f7668e05187 in __GI___libc_write (fd=2, buf=0x7f76177fac60, nbytes=47) at ../sysdeps/unix/sysv/linux/write.c:27
#1  0x00007f7668d801bd in _IO_new_file_write (f=0x7f76690e1680 <_IO_2_1_stderr_>, data=0x7f76177fac60, n=47) at fileops.c:1203
#2  0x00007f7668d80b2f in new_do_write (to_do=<optimized out>, data=0x7f76177fac60 "[warn] epoll_wait: Ung\303\274ltiger Dateideskriptor\n", fp=0x7f76690e1680 <_IO_2_1_stderr_>) at fileops.c:457
#3  _IO_new_file_xsputn (f=0x7f76690e1680 <_IO_2_1_stderr_>, data=<optimized out>, n=47) at fileops.c:1277
#4  0x00007f7668d53707 in buffered_vfprintf (s=s@entry=0x7f76690e1680 <_IO_2_1_stderr_>, format=format@entry=0x7f765157b6a8 "[%s] %s\n", args=args@entry=0x7f76177fd220) at vfprintf.c:2350
#5  0x00007f7668d50726 in _IO_vfprintf_internal (s=s@entry=0x7f76690e1680 <_IO_2_1_stderr_>, format=0x7f765157b6a8 "[%s] %s\n", ap=ap@entry=0x7f76177fd220) at vfprintf.c:1301
#6  0x00007f7668e274c6 in ___fprintf_chk (fp=0x7f76690e1680 <_IO_2_1_stderr_>, flag=1, format=<optimized out>) at fprintf_chk.c:35
#7  0x00007f76515639ad in event_logv_ () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#8  0x00007f7651563b44 in event_warn () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#9  0x00007f765156546c in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#10 0x00007f765155b114 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#11 0x00007f7659f7a8c4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#12 0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#13 0x00007f76598c9754 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#14 0x00007f7659f43e78 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#15 0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#16 0x00007f766470d6db in start_thread (arg=0x7f76177fe700) at pthread_create.c:463
#17 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f7628b93700 (LWP 9579)):
#0  0x00007f7664713ed9 in futex_reltimed_wait_cancelable (private=<optimized out>, reltime=0x7f7628b92750, expected=0, futex_word=0x7f7628b92938) at ../sysdeps/unix/sysv/linux/futex-internal.h:142
#1  __pthread_cond_wait_common (abstime=0x7f7628b927f0, mutex=0x7f7628b928e8, cond=0x7f7628b92910) at pthread_cond_wait.c:533
#2  __pthread_cond_timedwait (cond=0x7f7628b92910, mutex=0x7f7628b928e8, abstime=0x7f7628b927f0) at pthread_cond_wait.c:667
#3  0x00007f7659f74177 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#4  0x00007f7659f74ada in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#5  0x00007f7659f74bc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#6  0x00007f7659f32851 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f356b6 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f35974 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f7628b93700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f7629394700 (LWP 9578)):
#0  __lll_lock_wait_private () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95
#1  0x00007f7668e27474 in ___fprintf_chk (fp=0x7f76690e28b0 <_IO_stdfile_2_lock>, flag=1, format=0x7f765157b6a8 "[%s] %s\n") at fprintf_chk.c:30
#2  0x00007f76515639ad in event_logv_ () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#3  0x00007f7651563b44 in event_warn () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#4  0x00007f765156546c in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#5  0x00007f765155b114 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#6  0x00007f7659f7a8c4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f38f44 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f43e78 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#11 0x00007f766470d6db in start_thread (arg=0x7f7629394700) at pthread_create.c:463
#12 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f7629b95700 (LWP 9577)):
#0  __lll_lock_wait_private () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95
#1  0x00007f7668e27474 in ___fprintf_chk (fp=0x7f76690e28b0 <_IO_stdfile_2_lock>, flag=1, format=0x7f765157b6a8 "[%s] %s\n") at fprintf_chk.c:30
#2  0x00007f76515639ad in event_logv_ () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#3  0x00007f7651563b44 in event_warn () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#4  0x00007f765156546c in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#5  0x00007f765155b114 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6
#6  0x00007f7659f7a7dd in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#7  0x00007f7659f1149b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#8  0x00007f7659f43d21 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#9  0x00007f7659f76cd1 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineCore.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f7629b95700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f7630830700 (LWP 9570)):
#0  0x00007f7668e050b4 in __GI___libc_read (fd=8, buf=0x7f763082f7e0, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:27
#1  0x00007f7662885cd0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7662841027 in g_main_context_check () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f76628414e0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f766996415b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f766972d41a in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f766804e015 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#9  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007f766470d6db in start_thread (arg=0x7f7630830700) at pthread_create.c:463
#11 0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f7632a7f700 (LWP 9569)):
#0  0x00007f76647139f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55ef21a57bfc) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55ef21a57ba8, cond=0x55ef21a57bd0) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55ef21a57bd0, mutex=0x55ef21a57ba8) at pthread_cond_wait.c:655
#3  0x00007f7633e1bb1b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f7633e1b847 in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f766470d6db in start_thread (arg=0x7f7632a7f700) at pthread_create.c:463
#6  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f763cb64700 (LWP 9568)):
#0  0x00007f7668e09bf9 in __GI___poll (fds=0x7f763cb63938, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f7664d3b747 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f7664d3d36a in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f763ea8ed4a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007f766972ebc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f766470d6db in start_thread (arg=0x7f763cb64700) at pthread_create.c:463
#6  0x00007f7668e1688f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f766c4f7080 (LWP 9566)):
[KCrash Handler]
#6  0x00007f7667731a44 in QWebEngineView::page() const () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineWidgets.so.5
#7  0x00007f7667731b61 in QWebEngineView::setHtml(QString const&, QUrl const&) () from /usr/lib/x86_64-linux-gnu/libQt5WebEngineWidgets.so.5
#8  0x00007f753790e51f in MessageViewer::ViewerPrivate::displaySplashPage(QString const&, QHash<QString, QVariant> const&, QByteArray const&) () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#9  0x00007f753790e9b4 in MessageViewer::ViewerPrivate::displaySplashPage(QString const&) () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#10 0x00007f7537912653 in MessageViewer::ViewerPrivate::itemFetchResult(KJob*) () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#11 0x00007f7669936f3f in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007f766b087fcc in KJob::result(KJob*, KJob::QPrivateSignal) () from /usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5
#13 0x00007f766b088b01 in KJob::finishJob(bool) () from /usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5
#14 0x00007f766b088b62 in KJob::kill(KJob::KillVerbosity) () from /usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5
#15 0x00007f7668721fc1 in Akonadi::SessionPrivate::clear(bool) () from /usr/lib/x86_64-linux-gnu/libKF5AkonadiCore.so.5
#16 0x00007f766872207d in Akonadi::Session::~Session() () from /usr/lib/x86_64-linux-gnu/libKF5AkonadiCore.so.5
#17 0x00007f76687220a9 in Akonadi::Session::~Session() () from /usr/lib/x86_64-linux-gnu/libKF5AkonadiCore.so.5
#18 0x00007f76699349fb in QObjectPrivate::deleteChildren() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007f766993e4fb in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#20 0x00007f753790b7a9 in MessageViewer::ViewerPrivate::~ViewerPrivate() () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#21 0x00007f76699349fb in QObjectPrivate::deleteChildren() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f766a73919c in QWidget::~QWidget() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#23 0x00007f75378fee09 in MessageViewer::Viewer::~Viewer() () from /usr/lib/x86_64-linux-gnu/libKF5MessageViewer.so.5
#24 0x00007f76699349fb in QObjectPrivate::deleteChildren() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007f766a73919c in QWidget::~QWidget() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007f7539486cb9 in KMReaderWin::~KMReaderWin() () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#27 0x00007f76699349fb in QObjectPrivate::deleteChildren() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x00007f766a73919c in QWidget::~QWidget() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#29 0x00007f766a89f379 in QSplitter::~QSplitter() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#30 0x00007f76699349fb in QObjectPrivate::deleteChildren() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#31 0x00007f766a73919c in QWidget::~QWidget() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#32 0x00007f766a89f379 in QSplitter::~QSplitter() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#33 0x00007f75394be7b3 in KMMainWidget::deleteWidgets() () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#34 0x00007f75394d8c61 in KMMainWidget::destruct() () from /usr/lib/x86_64-linux-gnu/libkmailprivate.so.5
#35 0x00007f753988e7f6 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kmailpart.so
#36 0x00007f753988e959 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kmailpart.so
#37 0x00007f766bd00e3e in KontactInterface::Plugin::~Plugin() () from /usr/lib/x86_64-linux-gnu/libKF5KontactInterface.so.5
#38 0x00007f753a2fc646 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kontact_kmailplugin.so
#39 0x00007f753a2fc669 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kontact_kmailplugin.so
#40 0x00007f766bf2bdb6 in Kontact::MainWindow::~MainWindow() () from /usr/lib/x86_64-linux-gnu/libkontactprivate.so.5
#41 0x00007f766bf2bfa9 in Kontact::MainWindow::~MainWindow() () from /usr/lib/x86_64-linux-gnu/libkontactprivate.so.5
#42 0x00007f76699379b0 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#43 0x00007f766a73df4b in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#44 0x00007f766a846030 in QMainWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#45 0x00007f766b858bb1 in KMainWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5XmlGui.so.5
#46 0x00007f766b89e7c5 in KXmlGuiWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5XmlGui.so.5
#47 0x00007f766a6fd83c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#48 0x00007f766a704dd0 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#49 0x00007f7669907328 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#50 0x00007f7669909e87 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#51 0x00007f7669964b23 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#52 0x00007f7662841387 in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#53 0x00007f76628415c0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#54 0x00007f766284164c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#55 0x00007f766996413f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#56 0x00007f766990564a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#57 0x00007f766990e800 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#58 0x000055ef201544c5 in ?? ()
#59 0x00007f7668d16b97 in __libc_start_main (main=0x55ef201536b0, argc=1, argv=0x7ffd1afd0648, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd1afd0638) at ../csu/libc-start.c:310
#60 0x000055ef20154aea in _start ()

Reported using DrKonqi