Application: baloo_file (5.9.90)
 (Compiled from sources)
Qt Version: 5.4.1
Operating System: Linux 4.0.0-tamino x86_64
Distribution (Platform): Gentoo Packages

-- Information about the crash:
- What I was doing when the application crashed:
I was enabling File Search in System Settings.

An baloo_file_cleaner segmentation fault also appear, I assume it's releated to this one. Backtrace is as follows:
Application: baloo_file_cleaner (baloo_file_cleaner), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[KCrash Handler]
#6  mdb_txn_renew0 (txn=txn@entry=0xebb700) at mdb.c:2481
#7  0x00007f34212c1287 in mdb_txn_begin (env=0xebb600, parent=0x0, flags=<optimized out>, ret=0x7ffde70cfd70) at mdb.c:2700
#8  0x00007f342430f194 in Baloo::Database::open (this=this@entry=0x7ffde70cfe40, mode=mode@entry=Baloo::Database::OpenDatabase) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/engine/database.cpp:81
#9  0x0000000000413ad6 in main (argc=1, argv=<optimized out>) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/cleaner/main.cpp:62

The crash can be reproduced every time.

-- Backtrace:
Application: Baloo File Indexing Daemon (baloo_file), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fb831040800 (LWP 28650))]

Thread 2 (Thread 0x7fb82f8a8700 (LWP 28653)):
#0  0x00007fb840a169bd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fb8403039d2 in ?? () from /usr/lib64/libxcb.so.1
#2  0x00007fb840305557 in xcb_wait_for_event () from /usr/lib64/libxcb.so.1
#3  0x00007fb830fb4189 in ?? () from /usr/lib64/qt5/plugins/platforms/libqxcb.so
#4  0x00007fb8410f659e in ?? () from /usr/lib64/libQt5Core.so.5
#5  0x00007fb83c080370 in start_thread (arg=0x7fb82f8a8700) at pthread_create.c:310
#6  0x00007fb840a1fb8d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fb831040800 (LWP 28650)):
[KCrash Handler]
#6  mdb_txn_begin (env=0x0, parent=0x0, flags=131072, ret=0x7fff7408f688) at mdb.c:2608
#7  0x000000000041c15d in Baloo::FileIndexingQueue::fillQueue (this=0x184b490) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/fileindexingqueue.cpp:58
#8  0x0000000000418aaa in Baloo::IndexScheduler::slotScheduleIndexing (this=0x184a6c0) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/indexscheduler.cpp:271
#9  0x0000000000419464 in Baloo::IndexScheduler::IndexScheduler (this=0x184a6c0, db=<optimized out>, config=<optimized out>, parent=<optimized out>) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/indexscheduler.cpp:68
#10 0x00000000004148cc in Baloo::FileIndexer::FileIndexer (this=0x7fff7408fb40, db=0x7fff7408fbb0, config=0x7fff7408fbf0, parent=<optimized out>) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/fileindexer.cpp:39
#11 0x00000000004140ee in main (argc=1, argv=<optimized out>) at /tmp/portage/kde-plasma/baloo-9999/work/baloo-9999/src/file/main.cpp:93

Reported using DrKonqi