Bug 431030

Qt Version: 5.12.8
Frameworks Version: 5.68.0
Operating System: Linux 5.9.16-xanmod1 x86_64
Windowing system: X11
Distribution: Ubuntu 20.04.1 LTS

-- Information about the crash:
baloo_file_extractor crash indexing ebook files mobi and epub
I have a lot of files in a directorey, crash after index 8-15 files. Only in this directory. 
I chek and files looks good.

I delete index file. first run = true
Crash still here.

index file about 6,7 gbyte

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8

ADDITIONAL INFORMATION
Application: Estrattore file di Baloo (baloo_file_extractor), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fb4f8d18f80 (LWP 17150))]

Thread 3 (Thread 0x7fb4f75cc700 (LWP 17152)):
#0  0x00007fb4fbb66aff in __GI___poll (fds=0x7fb4e801a950, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fb4fad201ae in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fb4fad202e3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fb4fc104583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fb4fc0ab4db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fb4fbee3785 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fb4fd10eefa in ?? () from /lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007fb4fbee49d2 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fb4fb5df609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007fb4fbb73293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fb4f7e64700 (LWP 17151)):
#0  0x00007fb4fbb66aff in __GI___poll (fds=0x7fb4f7e63ca8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fb4facadc1a in ?? () from /lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fb4facaf90a in xcb_wait_for_event () from /lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fb4f865c298 in ?? () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007fb4fbee49d2 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fb4fb5df609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007fb4fbb73293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fb4f8d18f80 (LWP 17150)):
[KCrash Handler]
#6  0x00007fb4f6a6d452 in _opf_label_get_by_lang () from /lib/libepub.so.0
#7  0x00007fb4f6a6a089 in epub_tit_next () from /lib/libepub.so.0
#8  0x00007fb4f6aa26b8 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kfilemetadata/kfilemetadata_epubextractor.so
#9  0x000055a82d838b37 in ?? ()
#10 0x000055a82d839434 in ?? ()
#11 0x00007fb4fc0e55b6 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fb4fc0d8cf5 in QObject::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fb4fcac4a66 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fb4fcace0f0 in QApplication::notify(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#15 0x00007fb4fc0ac93a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fb4fc1038b0 in QTimerInfoList::activateTimers() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007fb4fc10419c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007fb4fad1ffbd in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007fb4fad20240 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007fb4fad202e3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fb4fc104565 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007fb4fc0ab4db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007fb4fc0b3246 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x000055a82d8377d4 in ?? ()
#25 0x00007fb4fba780b3 in __libc_start_main (main=0x55a82d837580, argc=1, argv=0x7fff1657d378, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff1657d368) at ../csu/libc-start.c:308
#26 0x000055a82d83788e in ?? ()
[Inferior 1 (process 17150) detached]