Application: systemsettings (1.0)
KDE Platform Version: 4.4.2 (KDE 4.4.2)
Qt Version: 4.6.2
Operating System: Linux 2.6.32-23-generic x86_64
Distribution: Ubuntu 10.04 LTS

-- Information about the crash:
I'm not exactly sure how to reproduce the crash, but it seems that either the system setting apllication or the plasma desktop crashes and restarts while searching for new application packages. I did have firefox open as well as Dolphin. I was also switching back and forth between Firefox and the application manager in the systems settings very often, comparing packages and doing package research.

The crash can be reproduced some of the time.

 -- Backtrace:
Application: System Settings (systemsettings), signal: Segmentation fault
[Current thread is 1 (Thread 0x7fa845356760 (LWP 27876))]

Thread 2 (Thread 0x7fa8355bc710 (LWP 27877)):
#0  0x00007fa840461a2d in __pthread_mutex_unlock_usercnt (mutex=0x2aa4cd8) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=0x2aa4cd8) at pthread_mutex_unlock.c:290
#2  0x00007fa83fae9ff1 in g_main_context_prepare () from /lib/libglib-2.0.so.0
#3  0x00007fa83faea318 in ?? () from /lib/libglib-2.0.so.0
#4  0x00007fa83faea8fc in g_main_context_iteration () from /lib/libglib-2.0.so.0
#5  0x00007fa843010566 in QEventDispatcherGlib::processEvents (this=0x2aa0e40, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:414
#6  0x00007fa842fe5992 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#7  0x00007fa842fe5d6c in QEventLoop::exec (this=0x7fa8355bbdb0, flags=) at kernel/qeventloop.cpp:201
#8  0x00007fa842eefd59 in QThread::exec (this=<value optimized out>) at thread/qthread.cpp:487
#9  0x00007fa842fc6178 in QInotifyFileSystemWatcherEngine::run (this=0x2aa3f10) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007fa842ef2775 in QThreadPrivate::start (arg=0x2aa3f10) at thread/qthread_unix.cpp:248
#11 0x00007fa84045d9ca in start_thread (arg=<value optimized out>) at pthread_create.c:300
#12 0x00007fa8428c86fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fa845356760 (LWP 27876)):
[KCrash Handler]
#5  0x00007fa842ffa0a3 in QObjectPrivate::isSignalConnected (sender=0x2d1c6d0, m=<value optimized out>, local_signal_index=11, argv=0x7fffc2509200) at kernel/qobject_p.h:227
#6  QMetaObject::activate (sender=0x2d1c6d0, m=<value optimized out>, local_signal_index=11, argv=0x7fffc2509200) at kernel/qobject.cpp:3218
#7  0x00007fa83497bd2f in PackageKit::Transaction::finished(PackageKit::Transaction::ExitStatus, unsigned int) () from /usr/lib/libpackagekit-qt.so.12
#8  0x00007fa834977399 in PackageKit::ClientPrivate::serviceOwnerChanged(QString const&, QString const&, QString const&) () from /usr/lib/libpackagekit-qt.so.12
#9  0x00007fa834978e88 in PackageKit::ClientPrivate::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libpackagekit-qt.so.12
#10 0x00007fa842ff9e3f in QMetaObject::activate (sender=0x289b2b0, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x0) at kernel/qobject.cpp:3293
#11 0x00007fa84335c09f in QDBusConnectionInterface::serviceOwnerChanged (this=0xd, _t1=<value optimized out>, _t2=<value optimized out>, _t3=<value optimized out>)
    at .moc/release-shared/moc_qdbusconnectioninterface.cpp:210
#12 0x00007fa84335c344 in QDBusConnectionInterface::qt_metacall (this=0x289b2b0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffc2509650)
    at .moc/release-shared/moc_qdbusconnectioninterface.cpp:137
#13 0x00007fa842ff9e3f in QMetaObject::activate (sender=0x289b2b0, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x0) at kernel/qobject.cpp:3293
#14 0x00007fa84335bfcf in QDBusConnectionInterface::NameOwnerChanged (this=0xd, _t1=<value optimized out>, _t2=<value optimized out>, _t3=<value optimized out>)
    at .moc/release-shared/moc_qdbusconnectioninterface.cpp:238
#15 0x00007fa84335c3ac in QDBusConnectionInterface::qt_metacall (this=0x289b2b0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffc2509a10)
    at .moc/release-shared/moc_qdbusconnectioninterface.cpp:141
#16 0x00007fa843320486 in QDBusConnectionPrivate::deliverCall (this=<value optimized out>, object=<value optimized out>, msg=<value optimized out>, metaTypes=..., slotIdx=<value optimized out>)
    at qdbusintegrator.cpp:904
#17 0x00007fa84332b05f in QDBusCallDeliveryEvent::placeMetaCall(QObject*) () from /usr/lib/libQtDBus.so.4
#18 0x00007fa842ff6d49 in QObject::event (this=0x289b2b0, e=0x2fd96f0) at kernel/qobject.cpp:1248
#19 0x00007fa843bd422c in QApplicationPrivate::notify_helper (this=0x263a820, receiver=0x289b2b0, e=0x2fd96f0) at kernel/qapplication.cpp:4300
#20 0x00007fa843bda6fb in QApplication::notify (this=0x7fffc250a500, receiver=0x289b2b0, e=0x2fd96f0) at kernel/qapplication.cpp:4183
#21 0x00007fa8448df526 in KApplication::notify (this=0x7fffc250a500, receiver=0x289b2b0, event=0x2fd96f0) at ../../kdeui/kernel/kapplication.cpp:302
#22 0x00007fa842fe706c in QCoreApplication::notifyInternal (this=0x7fffc250a500, receiver=0x289b2b0, event=0x2fd96f0) at kernel/qcoreapplication.cpp:704
#23 0x00007fa842fe97e7 in QCoreApplication::sendEvent (receiver=0x0, event_type=<value optimized out>, data=0x2609c30) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#24 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=<value optimized out>, data=0x2609c30) at kernel/qcoreapplication.cpp:1345
#25 0x00007fa8430109d3 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#26 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:276
#27 0x00007fa83fae68c2 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#28 0x00007fa83faea748 in ?? () from /lib/libglib-2.0.so.0
#29 0x00007fa83faea8fc in g_main_context_iteration () from /lib/libglib-2.0.so.0
#30 0x00007fa843010513 in QEventDispatcherGlib::processEvents (this=0x2609770, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:412
#31 0x00007fa843c8446e in QGuiEventDispatcherGlib::processEvents (this=0xd, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#32 0x00007fa842fe5992 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#33 0x00007fa842fe5d6c in QEventLoop::exec (this=0x7fffc250a450, flags=) at kernel/qeventloop.cpp:201
#34 0x00007fa842fe9aab in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#35 0x00000000004110d9 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../../systemsettings/app/main.cpp:49

Reported using DrKonqi