Application: baloo_file (5.22.0)

Qt Version: 5.5.1
Frameworks Version: 5.22.0
Operating System: Linux 4.4.0-22-generic x86_64
Distribution: Ubuntu 16.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:
I had entered search text to the plasma launcher. The same behaviour is encountered when using the application launcher (Alt+F2). 
- Unusual behavior I noticed:
After the plasma crash, the launchers are gone, to reappear again. Sometimes the launchers do not reappear. The opened windows remain fully functional in the meanwhile. 

-fix
Previously tried 
#balooctl status  // result is baloo not running
#balooctl enable //or
#balooctl start //  this would throw a lot of information about failure to index several files under my home folder. I tried to exclude /home/user from indexing but it did not prevent. 
I tried a method suggested by one user. 
#balooctl disable
#balooctl enable

this worked.

The crash can be reproduced every time.

-- Backtrace:
Application: Baloo File Indexing Daemon (baloo_file), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fb67acb5900 (LWP 1350))]

Thread 2 (Thread 0x7fb66e9e1700 (LWP 1658)):
[KCrash Handler]
#6  mdb_txn_begin (env=0x0, parent=0x0, flags=131072, ret=0x7fb66e9e0bf8) at mdb.c:2773
#7  0x000000000040f56d in ?? ()
#8  0x00007fb679784343 in QThreadPoolThread::run (this=0x1d892a0) at thread/qthreadpool.cpp:93
#9  0x00007fb67978784e in QThreadPrivate::start (arg=0x1d892a0) at thread/qthread_unix.cpp:331
#10 0x00007fb6783d16fa in start_thread (arg=0x7fb66e9e1700) at pthread_create.c:333
#11 0x00007fb678d80b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fb67acb5900 (LWP 1350)):
#0  0x00007fb678d709cd in read () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fb671d03f45 in ?? () from /usr/lib/nvidia-340/tls/libnvidia-tls.so.340.96
#2  0x00007fb675f4f6c0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fb675f0be04 in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fb675f0c2c0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fb675f0c42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007fb6799bea7f in QEventDispatcherGlib::processEvents (this=0x1bd1250, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#7  0x00007fb679965dea in QEventLoop::exec (this=this@entry=0x7ffdc59c0a00, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#8  0x00007fb67996de8c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1229
#9  0x000000000040a90c in ?? ()
#10 0x00007fb678c9a830 in __libc_start_main (main=0x40a590, argc=1, argv=0x7ffdc59c0d78, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffdc59c0d68) at ../csu/libc-start.c:291
#11 0x000000000040aac9 in _start ()

Possible duplicates by query: bug 353757, bug 353238.

Reported using DrKonqi