I don't have information about how to reproduce the bug. But I just have the backtrace.

Application: dolphin (20.12.0)

Qt Version: 5.15.2
Frameworks Version: 5.77.0
Operating System: Linux 5.4.0-58-generic x86_64
Windowing system: X11
Distribution: KDE neon User Edition 5.20

-- Backtrace:
Application: Dolphin (dolphin), signal: Aborted
Content of s_kcrashErrorMessage: (null)
[New LWP 9973]
[New LWP 9974]
[New LWP 9979]
[New LWP 16700]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007f160f039aff in __GI___poll (fds=fds@entry=0x7ffcc66ddae8, nfds=nfds@entry=1, timeout=timeout@entry=1000) at ../sysdeps/unix/sysv/linux/poll.c:29
[Current thread is 1 (Thread 0x7f16080ec8c0 (LWP 9972))]

Thread 5 (Thread 0x7f15eec47700 (LWP 16700)):
#0  __GI___libc_read (nbytes=10, buf=0x7f15eec46b1e, fd=26) at ../sysdeps/unix/sysv/linux/read.c:26
#1  __GI___libc_read (fd=26, buf=0x7f15eec46b1e, nbytes=10) at ../sysdeps/unix/sysv/linux/read.c:24
#2  0x00007f160a672975 in pa_read () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-13.99.so
#3  0x00007f160b46c416 in pa_mainloop_prepare () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#4  0x00007f160b46ceb4 in pa_mainloop_iterate () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#5  0x00007f160b46cf70 in pa_mainloop_run () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#6  0x00007f160b47b11d in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#7  0x00007f160a6a172c in ?? () from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-13.99.so
#8  0x00007f160b4bf609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f160f046293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f15ef7fe700 (LWP 9979)):
#0  0x00007f160f039aff in __GI___poll (fds=0x7f15e4005240, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f160aaf01ae in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f160aaf02e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f160cd80fbb in QEventDispatcherGlib::processEvents (this=0x7f15e4000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f160cd251ab in QEventLoop::exec (this=this@entry=0x7f15ef7fdce0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#5  0x00007f160cb3fa12 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#6  0x00007f160cb40bac in QThreadPrivate::start (arg=0x55750078df20) at thread/qthread_unix.cpp:329
#7  0x00007f160b4bf609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x00007f160f046293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f16066c9700 (LWP 9974)):
#0  0x00007f160f039aff in __GI___poll (fds=0x7f15f8015390, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f160aaf01ae in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f160aaf02e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f160cd80fbb in QEventDispatcherGlib::processEvents (this=0x7f15f8000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f160cd251ab in QEventLoop::exec (this=this@entry=0x7f16066c8cb0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#5  0x00007f160cb3fa12 in QThread::exec (this=this@entry=0x7f160de5ad80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#6  0x00007f160ddd6f4b in QDBusConnectionManager::run (this=0x7f160de5ad80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:179
#7  0x00007f160cb40bac in QThreadPrivate::start (arg=0x7f160de5ad80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:329
#8  0x00007f160b4bf609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f160f046293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f160748f700 (LWP 9973)):
#0  0x00007f160f039aff in __GI___poll (fds=0x7f160748ebe8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f160b4f5c1a in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f160b4f790a in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f16079add58 in QXcbEventQueue::run (this=0x5575004d3ad0) at qxcbeventqueue.cpp:228
#4  0x00007f160cb40bac in QThreadPrivate::start (arg=0x5575004d3ad0) at thread/qthread_unix.cpp:329
#5  0x00007f160b4bf609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f160f046293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f16080ec8c0 (LWP 9972)):
[KCrash Handler]
#6  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#7  0x00007f160ef49859 in __GI_abort () at abort.c:79
#8  0x00007f160efb43ee in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7f160f0de285 "%s\n") at ../sysdeps/posix/libc_fatal.c:155
#9  0x00007f160efbc47c in malloc_printerr (str=str@entry=0x7f160f0e05d0 "free(): double free detected in tcache 2") at malloc.c:5347
#10 0x00007f160efbe0ed in _int_free (av=0x7f160f10fb80 <main_arena>, p=0x557504732f90, have_lock=0) at malloc.c:4201
#11 0x00007f160ee5545f in KFileItemModel::slotClear() () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#12 0x00007f160eebf207 in DolphinView::setUrl(QUrl const&) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#13 0x00007f160f18491c in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_dolphin.so
#14 0x00007f160cd5d6be in QtPrivate::QSlotObjectBase::call (a=0x7ffcc66de9d0, r=0x55750113c3a0, this=0x55750134d880) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#15 doActivate<false> (sender=0x55750123dc30, signal_index=8, argv=0x7ffcc66de9d0) at kernel/qobject.cpp:3886
#16 0x00007f160cd56a87 in QMetaObject::activate (sender=sender@entry=0x55750123dc30, m=m@entry=0x7f160edda440 <KUrlNavigator::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x7ffcc66de9d0) at kernel/qobject.cpp:3946
#17 0x00007f160ed9a539 in KUrlNavigator::urlChanged (this=this@entry=0x55750123dc30, _t1=...) at ./obj-x86_64-linux-gnu/src/filewidgets/KF5KIOFileWidgets_autogen/include/moc_kurlnavigator.cpp:326
#18 0x00007f160ed9e654 in KUrlNavigator::setLocationUrl (this=0x55750123dc30, newUrl=...) at ./src/filewidgets/kurlnavigator.cpp:1110
#19 0x00007f160f18245c in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_dolphin.so
#20 0x00007f160f18257b in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_dolphin.so
#21 0x00007f160cd5d6be in QtPrivate::QSlotObjectBase::call (a=0x7ffcc66dec30, r=0x55750113c3a0, this=0x557501343ea0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#22 doActivate<false> (sender=0x55750130bac0, signal_index=9, argv=0x7ffcc66dec30) at kernel/qobject.cpp:3886
#23 0x00007f160ee44c99 in DolphinView::itemActivated(KFileItem const&) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#24 0x00007f160eeb6f5b in DolphinView::slotItemActivated(int) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#25 0x00007f160cd5d6be in QtPrivate::QSlotObjectBase::call (a=0x7ffcc66ded80, r=0x55750130bac0, this=0x557500f94030) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#26 doActivate<false> (sender=0x5575012fdd50, signal_index=3, argv=0x7ffcc66ded80) at kernel/qobject.cpp:3886
#27 0x00007f160ee42c72 in KItemListController::itemActivated(int) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#28 0x00007f160ee78e28 in KItemListController::onRelease(QPointF const&, QFlags<Qt::KeyboardModifier>, QFlags<Qt::MouseButton>, bool) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#29 0x00007f160ee78f19 in KItemListController::mouseReleaseEvent(QGraphicsSceneMouseEvent*, QTransform const&) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#30 0x00007f160ee7ab79 in KItemListController::processEvent(QEvent*, QTransform const&) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#31 0x00007f160ee8a0c6 in KItemListView::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libdolphinprivate.so.5
#32 0x00007f160d7fddc3 in QApplicationPrivate::notify_helper (this=this@entry=0x5575004c8d80, receiver=receiver@entry=0x55750130dba0, e=e@entry=0x7ffcc66df680) at kernel/qapplication.cpp:3632
#33 0x00007f160d806bb8 in QApplication::notify (this=0x7ffcc66e05e0, receiver=0x55750130dba0, e=0x7ffcc66df680) at kernel/qapplication.cpp:3156
#34 0x00007f160cd2669a in QCoreApplication::notifyInternal2 (receiver=0x55750130dba0, event=0x7ffcc66df680) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#35 0x00007f160db32f73 in QGraphicsScenePrivate::sendEvent (this=<optimized out>, event=0x7ffcc66df680, item=0x55750130dbb0) at graphicsview/qgraphicsscene.cpp:1254
#36 QGraphicsScenePrivate::sendEvent (this=<optimized out>, item=0x55750130dbb0, event=0x7ffcc66df680) at graphicsview/qgraphicsscene.cpp:1234
#37 0x00007f160db333b7 in QGraphicsScenePrivate::sendMouseEvent (this=this@entry=0x5575013250b0, mouseEvent=mouseEvent@entry=0x7ffcc66df680) at graphicsview/qgraphicsscene.cpp:1335
#38 0x00007f160db38500 in QGraphicsScene::mouseReleaseEvent (this=<optimized out>, mouseEvent=0x7ffcc66df680) at graphicsview/qgraphicsscene.cpp:4123
#39 0x00007f160db456e9 in QGraphicsScene::event (this=0x557501324fa0, event=0x7ffcc66df680) at graphicsview/qgraphicsscene.cpp:3436
#40 0x00007f160d7fddc3 in QApplicationPrivate::notify_helper (this=this@entry=0x5575004c8d80, receiver=receiver@entry=0x557501324fa0, e=e@entry=0x7ffcc66df680) at kernel/qapplication.cpp:3632
#41 0x00007f160d806bb8 in QApplication::notify (this=0x7ffcc66e05e0, receiver=0x557501324fa0, e=0x7ffcc66df680) at kernel/qapplication.cpp:3156
#42 0x00007f160cd2669a in QCoreApplication::notifyInternal2 (receiver=0x557501324fa0, event=0x7ffcc66df680) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#43 0x00007f160db62c5a in QGraphicsView::mouseReleaseEvent (this=0x557501325070, event=0x7ffcc66dfc90) at /usr/include/c++/9/bits/atomic_base.h:413
#44 0x00007f160d840c06 in QWidget::event (this=this@entry=0x557501325070, event=event@entry=0x7ffcc66dfc90) at kernel/qwidget.cpp:8663
#45 0x00007f160d8f0f82 in QFrame::event (this=0x557501325070, e=0x7ffcc66dfc90) at widgets/qframe.cpp:550
#46 0x00007f160db63aa1 in QGraphicsView::viewportEvent (this=0x557501325070, event=0x7ffcc66dfc90) at graphicsview/qgraphicsview.cpp:3014
#47 0x00007f160cd26403 in QCoreApplicationPrivate::sendThroughObjectEventFilters (event=<optimized out>, receiver=<optimized out>) at kernel/qcoreapplication.cpp:1189
#48 QCoreApplicationPrivate::sendThroughObjectEventFilters (receiver=receiver@entry=0x557501322850, event=event@entry=0x7ffcc66dfc90) at kernel/qcoreapplication.cpp:1178
#49 0x00007f160d7fddb2 in QApplicationPrivate::notify_helper (this=this@entry=0x5575004c8d80, receiver=receiver@entry=0x557501322850, e=e@entry=0x7ffcc66dfc90) at kernel/qapplication.cpp:3626
#50 0x00007f160d806e77 in QApplication::notify (this=<optimized out>, receiver=0x557501322850, e=0x7ffcc66dfc90) at kernel/qapplication.cpp:3076
#51 0x00007f160cd2669a in QCoreApplication::notifyInternal2 (receiver=0x557501322850, event=0x7ffcc66dfc90) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#52 0x00007f160d8060a7 in QApplicationPrivate::sendMouseEvent (receiver=0x557501322850, event=0x7ffcc66dfc90, alienWidget=0x557501322850, nativeWidget=0x557500575730, buttonDown=<optimized out>, lastMouseReceiver=..., spontaneous=true, onlyDispatchEnterLeave=false) at kernel/qapplication.cpp:2614
#53 0x00007f160d85be54 in QWidgetWindow::handleMouseEvent(QMouseEvent*) () at /usr/include/c++/9/bits/atomic_base.h:413
#54 0x00007f160d85f174 in QWidgetWindow::event (this=0x5575006dacc0, event=0x7ffcc66e0110) at kernel/qwidgetwindow.cpp:300
#55 0x00007f160d7fddc3 in QApplicationPrivate::notify_helper (this=this@entry=0x5575004c8d80, receiver=receiver@entry=0x5575006dacc0, e=e@entry=0x7ffcc66e0110) at kernel/qapplication.cpp:3632
#56 0x00007f160d806bb8 in QApplication::notify (this=0x7ffcc66e05e0, receiver=0x5575006dacc0, e=0x7ffcc66e0110) at kernel/qapplication.cpp:3156
#57 0x00007f160cd2669a in QCoreApplication::notifyInternal2 (receiver=0x5575006dacc0, event=0x7ffcc66e0110) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#58 0x00007f160d1084e8 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () at kernel/qguiapplication.cpp:2282
#59 0x00007f160d109b55 in QGuiApplicationPrivate::processWindowSystemEvent (e=0x557503bfe1d0) at kernel/qguiapplication.cpp:2002
#60 0x00007f160d0e17ac in QWindowSystemInterface::sendWindowSystemEvents (flags=flags@entry=...) at kernel/qwindowsysteminterface.cpp:1169
#61 0x00007f16079aed7e in xcbSourceDispatch (source=<optimized out>) at qxcbeventdispatcher.cpp:105
#62 0x00007f160aaeffbd in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#63 0x00007f160aaf0240 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#64 0x00007f160aaf02e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#65 0x00007f160cd80fa2 in QEventDispatcherGlib::processEvents (this=0x55750058e670, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#66 0x00007f160cd251ab in QEventLoop::exec (this=this@entry=0x7ffcc66e04b0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#67 0x00007f160cd2d354 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#68 0x00007f160f169fa2 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_dolphin.so
#69 0x00007f160ef4b0b3 in __libc_start_main (main=0x5574fea96060, argc=2, argv=0x7ffcc66e0788, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffcc66e0778) at ../csu/libc-start.c:308
#70 0x00005574fea9609e in _start ()
[Inferior 1 (process 9972) detached]


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION