After years of running well a recent update (maybe a KDE library update) made ktorrent start crashing. Below is the backtrace from one of them. I noticed that bugs #602324 and #599914 are similar but I don't think a crash from 15 years ago is relevant today. Those 2 old bugs should probably be closed. Thread 1 "ktorrent" received signal SIGSEGV, Segmentation fault. 0x00007ffff5786cb4 in QCoreApplicationPrivate::lockThreadPostEventList(QObject*) () from /lib/x86_64-linux-gnu/libQt6Core.so.6 (gdb) bt #0 0x00007ffff5786cb4 in QCoreApplicationPrivate::lockThreadPostEventList(QObject*) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #1 0x00007ffff57c96d8 in QObject::deleteLater() () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #2 0x00007ffff7d78417 in bt::AuthenticationMonitor::handleData() () at /lib/x86_64-linux-gnu/libKTorrent6.so.6 #3 0x00005555555b4b27 in ??? () #4 0x00007ffff57d5aef in ??? () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #5 0x00007ffff57d82ce in QTimer::timeout(QTimer::QPrivateSignal) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #6 0x00007ffff57c7f99 in QObject::event(QEvent*) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #7 0x00007ffff65b20a2 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib/x86_64-linux-gnu/libQt6Widgets.so.6 #8 0x00007ffff5787928 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #9 0x00007ffff58cb69a in QTimerInfoList::activateTimers() () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #10 0x00007ffff598e82c in ??? () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #11 0x00007ffff449ff65 in ??? () at /lib/x86_64-linux-gnu/libglib-2.0.so.0 #12 0x00007ffff44a2197 in ??? () at /lib/x86_64-linux-gnu/libglib-2.0.so.0 #13 0x00007ffff44a2900 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0 #14 0x00007ffff598c473 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #15 0x00007ffff5792adb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #16 0x00007ffff578a908 in QCoreApplication::exec() () at /lib/x86_64-linux-gnu/libQt6Core.so.6 #17 0x00005555555a751a in ??? () #18 0x00007ffff5033ca8 in __libc_start_call_main (main=main@entry=0x5555555a3ce0, argc=argc@entry=1, argv=argv@entry=0x7fffffffe458) at ../sysdeps/nptl/libc_start_call_main.h:58 #19 0x00007ffff5033d65 in __libc_start_main_impl (main=0x5555555a3ce0, argc=1, argv=0x7fffffffe458, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe448) at ../csu/libc-start.c:360 #20 0x00005555555a8461 in ??? () (gdb)