Hi, maybe it helps...

svn 1155499

Application: KTorrent (ktorrent), signal: Segmentation fault
[Current thread is 1 (Thread 0xb47bf710 (LWP 30584))]

Thread 2 (Thread 0xb23ffb70 (LWP 30587)):
#0 0xb4f16e16 in *__GI_clock_gettime (clock_id=-1259229196, tp=0xb23fef90) at ../sysdeps/unix/clock_gettime.c:100
#1 0xb670fedb in do_gettime () at tools/qelapsedtimer_unix.cpp:105
#2 qt_gettime () at tools/qelapsedtimer_unix.cpp:119
#3 0xb67e62f5 in QTimerInfoList::updateCurrentTime (this=0x83277d4) at kernel/qeventdispatcher_unix.cpp:339
#4 0xb67e633a in QTimerInfoList::timerWait (this=0x83277d4, tm=...) at kernel/qeventdispatcher_unix.cpp:442
#5 0xb67e43d8 in timerSourcePrepareHelper (src=<value optimized out>, timeout=0xb23ff0bc) at kernel/qeventdispatcher_glib.cpp:136
#6 0xb67e4465 in timerSourcePrepare (source=0x0, timeout=0xb4f1aff4) at kernel/qeventdispatcher_glib.cpp:169
#7 0xb4e87aca in g_main_context_prepare () from /lib/libglib-2.0.so.0
#8 0xb4e87ee9 in ?? () from /lib/libglib-2.0.so.0
#9 0xb4e884b8 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#10 0xb67e41cf in QEventDispatcherGlib::processEvents (this=0x8c7e1c8, flags=...) at kernel/qeventdispatcher_glib.cpp:414
#11 0xb67b4419 in QEventLoop::processEvents (this=0xb23ff290, flags=) at kernel/qeventloop.cpp:149
#12 0xb67b489a in QEventLoop::exec (this=0xb23ff290, flags=...) at kernel/qeventloop.cpp:201
#13 0xb66b1b5e in QThread::exec (this=0x8c7d5c0) at thread/qthread.cpp:490
#14 0xb679355b in QInotifyFileSystemWatcherEngine::run (this=0x8c7d5c0) at io/qfilesystemwatcher_inotify.cpp:248
#15 0xb66b4e39 in QThreadPrivate::start (arg=0x8c7d5c0) at thread/qthread_unix.cpp:266
#16 0xb663996e in start_thread (arg=0xb23ffb70) at pthread_create.c:300
#17 0xb5999a4e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 1 (Thread 0xb47bf710 (LWP 30584)):
[KCrash Handler]
#7 QHash<QModelIndex, QPersistentModelIndexData*>::isEmpty (this=0x54, akey=...) at ../../include/QtCore/../../src/corelib/tools/qhash.h:293
#8 QHash<QModelIndex, QPersistentModelIndexData*>::remove (this=0x54, akey=...) at ../../include/QtCore/../../src/corelib/tools/qhash.h:783
#9 0xb67aaa9d in QAbstractItemModelPrivate::removePersistentIndexData (this=0x0, data=0x95684c0) at kernel/qabstractitemmodel.cpp:542
#10 0xb67aae10 in QPersistentModelIndexData::destroy (data=0x95684c0) at kernel/qabstractitemmodel.cpp:83
#11 0xb67aaf35 in ~QPersistentModelIndex (this=0x8e970ac, __in_chrg=<value optimized out>) at kernel/qabstractitemmodel.cpp:155
#12 0xb626750d in ~QAbstractItemViewPrivate (this=0x8e96ed8, __in_chrg=<value optimized out>) at itemviews/qabstractitemview.cpp:115
#13 0xb62bc5ed in QTreeViewPrivate::~QTreeViewPrivate() () from /usr/lib/libQtGui.so.4
#14 0xb67cfd71 in QScopedPointerDeleter<QObjectData>::cleanup (this=0x8e908e0, __in_chrg=<value optimized out>) at ../../include/QtCore/../../src/corelib/tools/qscopedpointer.h:62
#15 ~QScopedPointer (this=0x8e908e0, __in_chrg=<value optimized out>) at ../../include/QtCore/../../src/corelib/tools/qscopedpointer.h:100
#16 ~QObject (this=0x8e908e0, __in_chrg=<value optimized out>) at kernel/qobject.cpp:963
#17 0xb5d018b1 in ~QWidget (this=0x8e908e0, __in_chrg=<value optimized out>) at kernel/qwidget.cpp:1579
#18 0xb61198e1 in ~QFrame (this=0x8e908e0, __in_chrg=<value optimized out>) at widgets/qframe.cpp:242
#19 0xb61b8344 in ~QAbstractScrollArea (this=0x8e908e0, __in_chrg=<value optimized out>) at widgets/qabstractscrollarea.cpp:526
#20 0xb6263f51 in ~QAbstractItemView (this=0x8e908e0, __in_chrg=<value optimized out>) at itemviews/qabstractitemview.cpp:598
#21 0xb62a8f01 in ~QTreeView (this=0x8e908e0, __in_chrg=<value optimized out>) at itemviews/qtreeview.cpp:208
#22 0xadde9f72 in ~PeerView (this=0x8e908e0, __in_chrg=<value optimized out>) at /usr/src/ktorrent-svn/ktorrent/plugins/infowidget/peerview.cpp:64
#23 0xadddd901 in kt::InfoWidgetPlugin::unload (this=0x8e77538) at /usr/src/ktorrent-svn/ktorrent/plugins/infowidget/infowidgetplugin.cpp:134
#24 0xb751096d in kt::PluginManager::unloadAll (this=0x84460a0) at /usr/src/ktorrent-svn/ktorrent/libktcore/plugin/pluginmanager.cpp:189
#25 0x080755f5 in kt::Core::onExit (this=0x83f5f60) at /usr/src/ktorrent-svn/ktorrent/ktorrent/core.cpp:908
#26 0x08077881 in kt::GUI::queryExit (this=0x83f58f0) at /usr/src/ktorrent-svn/ktorrent/ktorrent/gui.cpp:579
#27 0xb70c44e6 in KMainWindowPrivate::_k_shuttingDown (this=0x83f5990) at ../../kdeui/widgets/kmainwindow.cpp:1142
#28 0xb70c8ff6 in KMainWindow::qt_metacall (this=0x83f58f0, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbfa3a39c) at ./kmainwindow.moc:102
#29 0xb710e49a in KXmlGuiWindow::qt_metacall (this=0x83f58f0, _c=QMetaObject::InvokeMetaMethod, _id=38, _a=0xbfa3a39c) at ./kxmlguiwindow.moc:102
#30 0xb58a0cea in KParts::MainWindow::qt_metacall (this=0x83f58f0, _c=QMetaObject::InvokeMetaMethod, _id=38, _a=0xbfa3a39c) at ./mainwindow.moc:75
#31 0x0807ad1f in kt::GUI::qt_metacall (this=0x83f58f0, _c=QMetaObject::InvokeMetaMethod, _id=38, _a=0xbfa3a39c) at /usr/src/ktorrent-svn/ktorrent/build/ktorrent/gui.moc:102
#32 0xb67bb6ca in QMetaObject::metacall (object=0x83f58f0, cl=149546504, idx=38, argv=0xbfa3a39c) at kernel/qmetaobject.cpp:237
#33 0xb67ce455 in QMetaObject::activate (sender=0xbfa3a490, m=0xb68e7484, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3280
#34 0xb681f627 in QCoreApplication::aboutToQuit (this=0xbfa3a490) at .moc/release-shared/moc_qcoreapplication.cpp:131
#35 0xb67b8e76 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1014
#36 0xb5c9cef7 in QApplication::exec () at kernel/qapplication.cpp:3665
#37 0x0806a561 in main (argc=1, argv=0xbfa3a894) at /usr/src/ktorrent-svn/ktorrent/ktorrent/main.cpp:176

This:

#9 0xb67aaa9d in QAbstractItemModelPrivate::removePersistentIndexData (this=0x0, data=0x95684c0) at kernel/qabstractitemmodel.cpp:542
#10 0xb67aae10 in QPersistentModelIndexData::destroy (data=0x95684c0) at kernel/qabstractitemmodel.cpp:83

Looks like Qt code not checking for a 0 pointer.

Can you easily reproduce this ?

No, it happend once when I was about to restart the computer.

I should mention that I use a home built kernel: 2.6.35-rc6-hart01