SUMMARY
Just did serfing in browser when crash happened.

Application: baloo_file (baloo_file), signal: Aborted

[KCrash Handler]
#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:49
#5  0x00007fad774eb864 in __GI_abort () at abort.c:79
#6  0x00007fad769c1a83 in mdb_assert_fail (env=0x564c00f642f0, expr_txt=expr_txt@entry=0x7fad769c419b "pglast <= env->me_pglast", func=func@entry=0x7fad769c4940 <__func__.7464> "mdb_freelist_save", line=line@entry=3155, file=0x7fad769c4010 "mdb.c") at mdb.c:1542
#7  0x00007fad769bf205 in mdb_freelist_save (txn=0x564c00f656b0) at mdb.c:3108
#8  mdb_txn_commit (txn=0x564c00f656b0) at mdb.c:3643
#9  0x00007fad77f3fabb in Baloo::Transaction::commit() () from /lib/x86_64-linux-gnu/libKF5BalooEngine.so.5
#10 0x0000564bff7a20ae in ?? ()
#11 0x00007fad77aac812 in QThreadPoolThread::run (this=0x564c00f9d190) at thread/qthreadpool.cpp:99
#12 0x00007fad77aa8a41 in QThreadPrivate::start (arg=0x564c00f9d190) at thread/qthread_unix.cpp:342
#13 0x00007fad76a24590 in start_thread (arg=0x7fad725ad640) at pthread_create.c:463
#14 0x00007fad775de223 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

#1  0x00007fad7624772e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fad76247863 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fad77ce185b in QEventDispatcherGlib::processEvents (this=0x7fad6c000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#4  0x00007fad77c88a4b in QEventLoop::exec (this=this@entry=0x7fad730bfcb0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:136
#5  0x00007fad77aa78b2 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:118
#6  0x00007fad77f6d4cb in ?? () from /lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007fad77aa8a41 in QThreadPrivate::start (arg=0x7fad77fdbda0) at thread/qthread_unix.cpp:342
#8  0x00007fad76a24590 in start_thread (arg=0x7fad730c0640) at pthread_create.c:463
#9  0x00007fad775de223 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

#1  0x00007fad7624772e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fad76247863 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fad77ce1843 in QEventDispatcherGlib::processEvents (this=0x564c00f4a530, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007fad77c88a4b in QEventLoop::exec (this=this@entry=0x7ffea0cb91f0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:136
#5  0x00007fad77c90fc6 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:118
#6  0x0000564bff796cc0 in ?? ()
#7  0x00007fad774edcb2 in __libc_start_main (main=0x564bff796a70, argc=1, argv=0x7ffea0cb9578, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffea0cb9568) at ../csu/libc-start.c:314
#8  0x0000564bff796ebe in ?? ()
[Inferior 1 (process 49901) detached]



SOFTWARE/OS VERSIONS
Linux: 5.8.12

KDE Plasma Version: 5.19.5 
KDE Frameworks Version: 5.74.0
Qt Version: 5.14.2

ADDITIONAL INFORMATION
Kubuntu 20.10 (development branch)