Thanks for the bug report!

Interesting - I don't think that a crash like this has been reported before. I think that we need more information in order to understand the cause of the problem. Please install packages with debugging information that your distro provides for Dolphin. If possible, it would also help if you could provide a Valgrind log. Please see

https://community.kde.org/Dolphin/FAQ/Crashes

for details. Thanks for your help!

Application: Dolphin (dolphin), signal: Aborted
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f5322f87800 (LWP 1471))]

Thread 3 (Thread 0x7f5305d31700 (LWP 1472)):
#0  0x00007f53205dd2dd in poll () from /lib64/libc.so.6
#1  0x00007f531d4c080c in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f531d4c0934 in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f5321c32c4e in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#4  0x00007f5321c04d4f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#5  0x00007f5321c05045 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#6  0x00007f5321b045df in QThread::exec() () from /usr/lib64/qt4/libQtCore.so.4
#7  0x00007f5321be6623 in ?? () from /usr/lib64/qt4/libQtCore.so.4
#8  0x00007f5321b06c8f in ?? () from /usr/lib64/qt4/libQtCore.so.4
#9  0x00007f53218770a9 in start_thread () from /lib64/libpthread.so.0
#10 0x00007f53205e699d in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f53054d9700 (LWP 1473)):
#0  0x00007f53205dd2dd in poll () from /lib64/libc.so.6
#1  0x00007f531d4c080c in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f531d4c0934 in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f5321c32c4e in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#4  0x00007f5321c04d4f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#5  0x00007f5321c05045 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt4/libQtCore.so.4
#6  0x00007f5321b045df in QThread::exec() () from /usr/lib64/qt4/libQtCore.so.4
#7  0x00007f5321b06c8f in ?? () from /usr/lib64/qt4/libQtCore.so.4
#8  0x00007f53218770a9 in start_thread () from /lib64/libpthread.so.0
#9  0x00007f53205e699d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f5322f87800 (LWP 1471)):
[KCrash Handler]
#5  0x00007f5320533307 in raise () from /lib64/libc.so.6
#6  0x00007f5320534648 in abort () from /lib64/libc.so.6
#7  0x00007f5321afc804 in qt_message_output(QtMsgType, char const*) () from /usr/lib64/qt4/libQtCore.so.4
#8  0x00007f5321afc989 in ?? () from /usr/lib64/qt4/libQtCore.so.4
#9  0x00007f5321afd194 in qFatal(char const*, ...) () from /usr/lib64/qt4/libQtCore.so.4
#10 0x00007f5315d1bb8c in KItemListSizeHintResolver::sizeHint(int) () from /usr/lib64/libdolphinprivate.so.4
#11 0x00007f5315d1f511 in KItemListViewLayouter::doLayout() () from /usr/lib64/libdolphinprivate.so.4
#12 0x00007f5315d1f7e9 in KItemListViewLayouter::firstVisibleIndex() const () from /usr/lib64/libdolphinprivate.so.4
#13 0x00007f5315cfe3d8 in KItemListView::slotItemsMoved(KItemRange const&, QList<int> const&) () from /usr/lib64/libdolphinprivate.so.4
#14 0x00007f5315cf9a6f in KItemListView::setModel(KItemModelBase*) () from /usr/lib64/libdolphinprivate.so.4
#15 0x00007f5315cf4945 in KItemListController::setView(KItemListView*) () from /usr/lib64/libdolphinprivate.so.4
#16 0x00007f531695f398 in PlacesPanel::showEvent (this=0x27badc0, event=0x7fff5717e7e0) at /tmp/kde-baseapps-4.12.3/dolphin/src/panels/places/placespanel.cpp:111
#17 0x00007f5320dd722e in QWidget::event(QEvent*) () from /usr/lib64/qt4/libQtGui.so.4
#18 0x00007f5320d89dcc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/qt4/libQtGui.so.4
#19 0x00007f5320d8c73b in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/qt4/libQtGui.so.4
#20 0x00007f53229b741a in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#21 0x00007f5321c060fd in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib64/qt4/libQtCore.so.4
#22 0x00007f5320dda577 in QWidgetPrivate::show_helper() () from /usr/lib64/qt4/libQtGui.so.4
#23 0x00007f5320ddadea in QWidgetPrivate::showChildren(bool) () from /usr/lib64/qt4/libQtGui.so.4
#24 0x00007f5320dda47d in QWidgetPrivate::show_helper() () from /usr/lib64/qt4/libQtGui.so.4
#25 0x00007f5320ddadea in QWidgetPrivate::showChildren(bool) () from /usr/lib64/qt4/libQtGui.so.4
#26 0x00007f5320dda47d in QWidgetPrivate::show_helper() () from /usr/lib64/qt4/libQtGui.so.4
#27 0x00007f5320dda862 in QWidget::setVisible(bool) () from /usr/lib64/qt4/libQtGui.so.4
#28 0x00007f5316942426 in show (this=<optimized out>) at /usr/include/qt4/QtGui/qwidget.h:497
#29 DolphinApplication::DolphinApplication (this=0x7fff5717eb90) at /tmp/kde-baseapps-4.12.3/dolphin/src/dolphinapplication.cpp:37
#30 0x00007f5316957561 in kdemain (argc=5, argv=0x23354e0) at /tmp/kde-baseapps-4.12.3/dolphin/src/main.cpp:89
#31 0x00000000004080d5 in _start ()

==4994== Memcheck, a memory error detector
==4994== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==4994== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==4994== Command: dolphin
==4994== 
kdeinit4: Shutting down running client.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
kbuildsycoca4 running...
This backend is only for XRandR 1.1, your version is:  1 . 4 
QObject::connect: Cannot connect (null)::deviceFound(Device*) to BlueDevilDaemon::deviceFound(Device*)
QObject::connect: Cannot connect QTimer::timeout() to (null)::stopDiscovery()
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
kded(5000)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
QDBusConnection: name 'org.kde.kglobalaccel' had owner '' but we thought it was ':1.5'
QDBusObjectPath: invalid path ""
No outputs have backlight property
QDBusObjectPath: invalid path ""
kded(5000) ColorD::addOutput: Failed to register device: "device id 'xrandr-ASUS VH222H-A4LMTF039408' already exists" 
kded(5000) ProfileUtils::createIccProfile: EDID ICC Profile already exists "/home/stefano/.local/share/icc/edid-603e25b6ae0b3668f6794df8cfe7c4f8.icc" 
QInotifyFileSystemWatcherEngine::addPaths: inotify_add_watch failed: File o directory non esistente
QFileSystemWatcher: failed to add paths: /home/stefano/.kde4/share/config/activitymanager-pluginsrc
kded(5000) PowerDevil::Core::loadProfile: The profile  "AC" tried to activate "BrightnessControl" a non existent action. This is usually due to an installation problem or to a configuration problem. or simlpy the action is not supported 
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
klauncher: Exiting on signal 15
kdeinit4: Shutting down running client.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
KDE Daemon (kded) already running.
kbuildsycoca4 running...
kbuildsycoca4(5049) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5049) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5049) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kio_file(5051) kdemain: Starting 5051
klauncher: Exiting on signal 15
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
kdeinit4: Shutting down running client.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
KDE Daemon (kded) already running.
kbuildsycoca4 running...
kbuildsycoca4(5461) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5461) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5461) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kio_file(5462) kdemain: Starting 5462
klauncher: Exiting on signal 15
kdeinit4: Shutting down running client.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
KDE Daemon (kded) already running.
kbuildsycoca4 running...
kbuildsycoca4(5479) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5479) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kbuildsycoca4(5479) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file. 
kio_file(5480) kdemain: Starting 5480
kio_file(5480) kdemain: Done
kio_file(5481) kdemain: Starting 5481
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
dolphin(4994)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:
==4994== 
==4994== HEAP SUMMARY:
==4994==     in use at exit: 414,917 bytes in 4,406 blocks
==4994==   total heap usage: 1,104,089 allocs, 1,099,683 frees, 150,393,413 bytes allocated
==4994== 
==4994== LEAK SUMMARY:
==4994==    definitely lost: 3,048 bytes in 29 blocks
==4994==    indirectly lost: 9,420 bytes in 81 blocks
==4994==      possibly lost: 12,613 bytes in 155 blocks
==4994==    still reachable: 389,836 bytes in 4,141 blocks
==4994==         suppressed: 0 bytes in 0 blocks
==4994== Rerun with --leak-check=full to see details of leaked memory
==4994== 
==4994== For counts of detected and suppressed errors, rerun with: -v
==4994== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 1 from 1)
kio_file(5481) kdemain: Done
klauncher: Exiting on signal 15

Thanks, but it seems that some debugging info is still missing (some line numbers in the interesting parts of the backtrace are still missing). Moreover, the Valgrind log doesn't show anything unusual - was the log taken when Dolphin was running normally, without crash? If possible, please create a new Valgrind log of a crashing Dolphin session. Thanks!

Sorry but when I start dolphin with valgrind it not segfault and now when it start without valgrind it shows Signal: Aborted instead of Segfault.
When I start as root it not segfault nor aborted. It is an headache situation.

Given that this was a report from Gentoo, I assume this is long fixed.