Confirmed, it's a bug in Nepomuk...

Lukas

Just got a similar but different backtrace leading up to NepoMuk that segfaults in different code:

Application: KGet (kget), signal SIGSEGV

Thread 1 (Thread 0xb5e7c700 (LWP 3664)):
[KCrash Handler]
#6  0xb6939ee8 in QUrl::isEmpty (this=0xb66fb121) at /home/kde-devel/kde/src/qt-copy/src/corelib/io/qurl.cpp:3805
#7  0xb6b40f7f in Nepomuk::ResourceData::isValid (this=0xb66fb10d) at /home/kde-devel/kde/src/KDE/kdelibs/nepomuk/core/resourcedata.cpp:467
#8  0xb6b5e320 in Nepomuk::Resource::isValid (this=0x82c6418) at /home/kde-devel/kde/src/KDE/kdelibs/nepomuk/core/resource.cpp:262
#9  0xb7c1805e in NepomukHandler::saveFileProperties (this=0x82c6410) at /home/kde-devel/kde/src/KDE/kdenetwork/kget/core/nepomukhandler.cpp:62
#10 0xb7c03061 in Transfer::setStatus (this=0x8294e10, jobStatus=Job::Finished, text=@0xbfc98920, pix=@0xbfc9890c) at /home/kde-devel/kde/src/KDE/kdenetwork/kget/core/transfer.cpp:220
#11 0xb5e6d062 in TransferKio::slotResult (this=0x8294e08, kioJob=0x82c6410) at /home/kde-devel/kde/src/KDE/kdenetwork/kget/transfer-plugins/kio/transferKio.cpp:124
#12 0xb5e6d39c in TransferKio::qt_metacall (this=0x8294e08, _c=QMetaObject::InvokeMetaMethod, _id=5, _a=0xbfc98a4c)
    at /home/kde-devel/kde/build/KDE/kdenetwork/kget/transfer-plugins/kio/transferKio.moc:90
#13 0xb699c81b in QMetaObject::activate (sender=0x82c6410, from_signal_index=<value optimized out>, to_signal_index=7, argv=0xb66fb121)
    at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3010
#14 0xb699ceb2 in QMetaObject::activate (sender=0x82c6410, m=0xb77bc508, local_signal_index=3, argv=0xbfc98a4c) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3080
#15 0xb76ab694 in KJob::result (this=0x82c6410, _t1=0x82c6410) at /home/kde-devel/kde/build/KDE/kdelibs/kdecore/kjob.moc:186
#16 0xb76abbd2 in KJob::emitResult (this=0x82c6410) at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/jobs/kjob.cpp:290
#17 0xb79145b0 in KIO::FileCopyJob::slotResult (this=0x82c6410, job=0x81cc058) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/job.cpp:2191
#18 0xb7914f97 in KIO::FileCopyJob::qt_metacall (this=0x82c6410, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0xbfc98bac) at /home/kde-devel/kde/build/KDE/kdelibs/kio/jobclasses.moc:658
#19 0xb699c81b in QMetaObject::activate (sender=0x81cc058, from_signal_index=<value optimized out>, to_signal_index=7, argv=0xb66fb121)
    at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3010
#20 0xb699ceb2 in QMetaObject::activate (sender=0x81cc058, m=0xb77bc508, local_signal_index=3, argv=0xbfc98bac) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3080
#21 0xb76ab694 in KJob::result (this=0x81cc058, _t1=0x81cc058) at /home/kde-devel/kde/build/KDE/kdelibs/kdecore/kjob.moc:186
#22 0xb76abbd2 in KJob::emitResult (this=0x81cc058) at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/jobs/kjob.cpp:290
#23 0xb790e019 in KIO::SimpleJob::slotFinished (this=0x81cc058) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/job.cpp:498
#24 0xb790e3f2 in KIO::TransferJob::slotFinished (this=0x81cc058) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/job.cpp:967
#25 0xb79153c9 in KIO::TransferJob::qt_metacall (this=0x81cc058, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbfc98df8) at /home/kde-devel/kde/build/KDE/kdelibs/kio/jobclasses.moc:336
#26 0xb699c81b in QMetaObject::activate (sender=0x81cd740, from_signal_index=<value optimized out>, to_signal_index=8, argv=0xb66fb121)
    at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3010
#27 0xb699ceb2 in QMetaObject::activate (sender=0x81cd740, m=0xb7a92ec4, local_signal_index=4, argv=0x0) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3080
#28 0xb79b71e1 in KIO::SlaveInterface::finished (this=0x81cd740) at /home/kde-devel/kde/build/KDE/kdelibs/kio/slaveinterface.moc:163
#29 0xb79b916a in KIO::SlaveInterface::dispatch (this=0x81cd740, _cmd=104, rawdata=@0xbfc98fa4) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slaveinterface.cpp:176
#30 0xb79b9056 in KIO::SlaveInterface::dispatch (this=0x81cd740) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slaveinterface.cpp:91
#31 0xb79ab6da in KIO::Slave::gotInput (this=0x81cd740) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slave.cpp:319
#32 0xb79acb32 in KIO::Slave::qt_metacall (this=0x81cd740, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbfc990a8) at /home/kde-devel/kde/build/KDE/kdelibs/kio/slave.moc:75
#33 0xb699c81b in QMetaObject::activate (sender=0x82b8a10, from_signal_index=<value optimized out>, to_signal_index=4, argv=0xb66fb121)
    at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3010
#34 0xb699ceb2 in QMetaObject::activate (sender=0x82b8a10, m=0xb7a8fb20, local_signal_index=0, argv=0x0) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:3080
#35 0xb78dd427 in KIO::Connection::readyRead (this=0x82b8a10) at /home/kde-devel/kde/build/KDE/kdelibs/kio/connection.moc:84
#36 0xb78de363 in KIO::ConnectionPrivate::dequeue (this=0x81a89b8) at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/connection.cpp:82
#37 0xb78df29d in KIO::Connection::qt_metacall (this=0x82b8a10, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x8348be8) at /home/kde-devel/kde/build/KDE/kdelibs/kio/connection.moc:72
#38 0xb699618b in QMetaCallEvent::placeMetaCall (this=0x838cf58, object=0x82b8a10) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:535
#39 0xb69981d1 in QObject::event (this=0x82b8a10, e=0x838cf58) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qobject.cpp:1140
#40 0xb6dde59c in QApplicationPrivate::notify_helper (this=0x80c84e8, receiver=0x82b8a10, e=0x838cf58) at /home/kde-devel/kde/src/qt-copy/src/gui/kernel/qapplication.cpp:3772
#41 0xb6de3119 in QApplication::notify (this=0xbfc998a8, receiver=0x82b8a10, e=0x838cf58) at /home/kde-devel/kde/src/qt-copy/src/gui/kernel/qapplication.cpp:3366
#42 0xb7de9313 in KApplication::notify (this=0xbfc998a8, receiver=0x82b8a10, event=0x838cf58) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:311
#43 0xb6987ab9 in QCoreApplication::notifyInternal (this=0xbfc998a8, receiver=0x82b8a10, event=0x838cf58) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qcoreapplication.cpp:587
#44 0xb6988e69 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x80b1438) at ../../include/QtCore/../../../../src/qt-copy/src/corelib/kernel/qcoreapplication.h:215
#45 0xb698908d in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at /home/kde-devel/kde/src/qt-copy/src/corelib/kernel/qcoreapplication.cpp:1091
#46 0xb69b306f in postEventSourceDispatch (s=0x80c38c0) at ../../include/QtCore/../../../../src/qt-copy/src/corelib/kernel/qcoreapplication.h:220
#47 0xb63a1cbe in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#48 0xb63a5093 in ?? () from /usr/lib/libglib-2.0.so.0
#49 0x080c3838 in ?? ()
#50 0x00000000 in ?? ()

*** Bug 168190 has been marked as a duplicate of this bug. ***

*** Bug 168431 has been marked as a duplicate of this bug. ***

I was not able to reproduce this. Does this still happen with current trunk?

Yep, still there, I will attach a new backtrace...

Lukas

Created attachment 26669 [details]
backtrace

Still occurs here, same backtrace. Code checked out from svn trunk 6th August 8am GMT.

Reassigned to kget, because after some hours of trying to fix it I am quite sure that it is no Nepomuk bug.

There is NepomukHandler::saveFileProperties() call from  m_nepomukHandler->saveFileProperties(); in transfer.cpp which then leads to the crash.

Well at that point m_nepomukHandler doesn't point to a NepomukHandler instance anymore. I tried to figure out where the bug in kget is but i have no clue, because there is no direct way to change the m_nepomukHandler pointer (ok there is, but that is not used.). But the address it points to is changed from the one set in the constrcutor of the Transfer class.

KGet nepomuk integration has been reworked quite a lot. If you still can reproduce this bug, please comment here.