After running download for some time (4-10 hours) Ktorrent crashes.
This happens with SVN-version from 31 Dec.
Earlier version (approx 20 dec) was running without problem for over a week.

When crashing I read "mmapfile memory allocation failed" or something similar (only shows for 1/2 sec, then main window closes) in log-window.

I currently downloads a torrent of 8,2 GB, with 2095 Chunks, when crash i read over 200 chunks currently downloading.

Got a backtrace ?

No, i currently don't have a backtrace.

But I found another way to crash KTorrent.

Uncheck or chech a file (not 100% downloaded) on the Files Tab.

Backtrace:
Using host libthread_db library "/lib/tls/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread 1096932032 (LWP 24634)]
[KCrash handler]
#7 0x4156858c in memcpy () from /lib/tls/libc.so.6
#8 0x40ee8e89 in QSocket::writeBlock () from /usr/lib/qt3/lib/libqt-mt.so.3
#9 0x40069627 in bt::Peer::sendData () from /opt/kde3/lib/libktorrent.so.0
#10 0x4008556c in bt::PacketWriter::sendPacket ()
from /opt/kde3/lib/libktorrent.so.0
#11 0x400855ba in bt::PacketWriter::queuePacket ()
from /opt/kde3/lib/libktorrent.so.0
#12 0x40085ce4 in bt::PacketWriter::sendChunk ()
from /opt/kde3/lib/libktorrent.so.0
#13 0x40083e99 in bt::PeerUploader::update ()
from /opt/kde3/lib/libktorrent.so.0
#14 0x4007465c in bt::Uploader::update () from /opt/kde3/lib/libktorrent.so.0
#15 0x40077948 in bt::TorrentControl::update ()
from /opt/kde3/lib/libktorrent.so.0
#16 0x08066e49 in KTorrentCore::update ()
#17 0x0806a447 in KTorrentCore::qt_invoke ()
#18 0x40ce9a49 in QObject::activate_signal ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#19 0x40ce9ef0 in QObject::activate_signal ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#20 0x4102d959 in QTimer::timeout () from /usr/lib/qt3/lib/libqt-mt.so.3
#21 0x40d0dd4f in QTimer::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#22 0x40c89d41 in QApplication::internalNotify ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#23 0x40c8a6b9 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#24 0x40904fce in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#25 0x40c7eab8 in QEventLoop::activateTimers ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#26 0x40c37f4f in QEventLoop::processEvents ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#27 0x40ca0c53 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#28 0x40c896bf in QApplication::enter_loop ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#29 0x40249040 in KIO::NetAccess::enter_loop () from /opt/kde3/lib/libkio.so.4
#30 0x402ab3bb in KIO::NetAccess::dircopyInternal ()
from /opt/kde3/lib/libkio.so.4
#31 0x402c103c in KIO::NetAccess::move () from /opt/kde3/lib/libkio.so.4
#32 0x402c116e in KIO::NetAccess::move () from /opt/kde3/lib/libkio.so.4
#33 0x40056236 in bt::Move () from /opt/kde3/lib/libktorrent.so.0
#34 0x4008ea4b in bt::MultiFileCache::downloadStatusChanged ()
from /opt/kde3/lib/libktorrent.so.0
#35 0x4008f399 in bt::MultiFileCache::qt_invoke ()
from /opt/kde3/lib/libktorrent.so.0
#36 0x40ce99ac in QObject::activate_signal ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#37 0x40094ddb in bt::TorrentFile::downloadStatusChanged ()
from /opt/kde3/lib/libktorrent.so.0
#38 0x40094ed2 in bt::TorrentFile::setDoNotDownload ()
from /opt/kde3/lib/libktorrent.so.0
#39 0x400a2220 in kt::FileTreeItem::stateChange ()
from /opt/kde3/lib/libktorrent.so.0
#40 0x40dc8401 in QCheckListItem::stateChange ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#41 0x40dcc98c in QCheckListItem::setState ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#42 0x40dcccb1 in QCheckListItem::setState ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#43 0x40dd3f88 in QCheckListItem::activate ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#44 0x40dd20d6 in QListView::contentsMousePressEventEx ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#45 0x40dd2b24 in QListView::contentsMousePressEvent ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#46 0x405ab1e7 in KListView::contentsMousePressEvent ()
from /opt/kde3/lib/libkdeui.so.4
#47 0x40e04218 in QScrollView::viewportMousePressEvent ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#48 0x40e01359 in QScrollView::eventFilter ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#49 0x40dcd1b6 in QListView::eventFilter ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#50 0x40ce978e in QObject::activate_filters ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#51 0x40ce980b in QObject::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#52 0x40d2339c in QWidget::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#53 0x40c89d41 in QApplication::internalNotify ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#54 0x40c8aea8 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#55 0x40904fce in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#56 0x40c24cd8 in QETWidget::translateMouseEvent ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#57 0x40c23afb in QApplication::x11ProcessEvent ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#58 0x40c37bea in QEventLoop::processEvents ()
from /usr/lib/qt3/lib/libqt-mt.so.3
#59 0x40ca0c39 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#60 0x40ca0b36 in QEventLoop::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#61 0x40c8968f in QApplication::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#62 0x0805b047 in main ()

I don't get any crashes when I check or uncheck a file which is not fully downloaded. Does this happen with all torrents, or just one ?

The files i uncheck have chunks currently downloading.

OK, it should be fixed now.