Version:           3.5.2 (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu1 dapper)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.15-17-686

About twice a day konqueror will crash for me, always when closing a tab. I have not been able to reproduce this problem reliably, but I do have a stack trace:

[KCrash handler]
#6  0x76911e84 in pthread_mutex_lock ()
   from /lib/tls/i686/cmov/libpthread.so.0
#7  0x77d7e70e in pthread_mutex_lock () from /lib/tls/i686/cmov/libc.so.6
#8  0x76eaea3c in XUnlockDisplay () from /usr/lib/libX11.so.6
#9  0x76ecbf54 in XrmQGetResource () from /usr/lib/libX11.so.6
#10 0x76ecc0b5 in XrmGetResource () from /usr/lib/libX11.so.6
#11 0x76ea19ea in XGetErrorDatabaseText () from /usr/lib/libX11.so.6
#12 0x76ea1c99 in XGetErrorText () from /usr/lib/libX11.so.6
#13 0x77187698 in qt_badwindow () from /usr/lib/libqt-mt.so.3
#14 0x7781cc03 in KApplication::xErrhandler () from /usr/lib/libkdecore.so.4
#15 0x7781cc3c in KApplication::xErrhandler () from /usr/lib/libkdecore.so.4
#16 0x76ec4cea in _XError () from /usr/lib/libX11.so.6
#17 0x76ec529e in _XReply () from /usr/lib/libX11.so.6
#18 0x76ebcee3 in XSync () from /usr/lib/libX11.so.6
#19 0x76cb79c4 in QXEmbed::~QXEmbed () from /usr/lib/libkdeui.so.4
#20 0x75db0aef in NSPluginInstance::~NSPluginInstance ()
   from /usr/lib/kde3/libnsplugin.so
#21 0x75dacef0 in PluginPart::closeURL () from /usr/lib/kde3/libnsplugin.so
#22 0x761af3d6 in KHTMLPart::closeURL () from /usr/lib/libkhtml.so.4
#23 0x761af359 in KHTMLPart::closeURL () from /usr/lib/libkhtml.so.4
#24 0x761af359 in KHTMLPart::closeURL () from /usr/lib/libkhtml.so.4
#25 0x761af845 in KHTMLPart::~KHTMLPart () from /usr/lib/libkhtml.so.4
#26 0x7683c0ed in KonqView::~KonqView () from /usr/lib/libkdeinit_konqueror.so
#27 0x7685d068 in KonqViewManager::removeTab ()
   from /usr/lib/libkdeinit_konqueror.so
#28 0x7685d255 in KonqMainWindow::slotRemoveTab ()
   from /usr/lib/libkdeinit_konqueror.so
#29 0x76889924 in KonqMainWindow::qt_invoke ()
   from /usr/lib/libkdeinit_konqueror.so
#30 0x77273e29 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#31 0x772748c4 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#32 0x7760f89f in QButton::clicked () from /usr/lib/libqt-mt.so.3
#33 0x7730f46a in QButton::mouseReleaseEvent () from /usr/lib/libqt-mt.so.3
#34 0x772ae5fd in QWidget::event () from /usr/lib/libqt-mt.so.3
#35 0x77209dc6 in QApplication::internalNotify () from /usr/lib/libqt-mt.so.3
#36 0x7720a350 in QApplication::notify () from /usr/lib/libqt-mt.so.3
#37 0x778d6ced in KApplication::notify () from /usr/lib/libkdecore.so.4
#38 0x7719b15d in QApplication::sendSpontaneousEvent ()
   from /usr/lib/libqt-mt.so.3
#39 0x7719680b in QETWidget::translateMouseEvent ()
   from /usr/lib/libqt-mt.so.3
#40 0x77194cf1 in QApplication::x11ProcessEvent () from /usr/lib/libqt-mt.so.3
#41 0x771ae473 in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#42 0x772228b7 in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#43 0x772227da in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#44 0x772088d5 in QApplication::exec () from /usr/lib/libqt-mt.so.3
#45 0x76883a51 in kdemain () from /usr/lib/libkdeinit_konqueror.so
#46 0x77f404f4 in kdeinitmain () from /usr/lib/kde3/konqueror.so
#47 0x0804e063 in ?? ()
#48 0x00000002 in ?? ()
#49 0x080d2a60 in ?? ()
#50 0x00000001 in ?? ()
#51 0x00000000 in ?? (