Version:            (using KDE KDE 3.3.1)
Installed from:    Compiled From Sources
Compiler:          gcc 2.95.3 
OS:                Linux

I hit the Decrease Font Sizes toolbar button perhaps 3 times in succession (which all worked), and then the Increase Font Sizes button (which had no effect). Then I hit the Increase Font Sizes button again, and Konqueror crashed (without increasing the font sizes first). I didn't do anything else between hitting these buttons. I was displaying a Qt documentation page (QMainWindow 3.3, probably).

[New Thread 1024 (LWP 1438)]
[New Thread 2049 (LWP 1932)]
[KCrash handler]
#6  0x41311ff1 in kill () from /lib/libc.so.6
#7  0x4124fb02 in raise () from /lib/libpthread.so.0
#8  0x413133f1 in abort () from /lib/libc.so.6
#9  0x4130c018 in __assert_fail () from /lib/libc.so.6
#10 0x419e9c39 in khtml::RenderBlock::createLineBoxes ()
   from /opt/kde3.3/lib/libkhtml.so.4
#11 0x419e9d70 in khtml::RenderBlock::createLineBoxes ()
   from /opt/kde3.3/lib/libkhtml.so.4
#12 0x419e9e56 in khtml::RenderBlock::constructLine ()
   from /opt/kde3.3/lib/libkhtml.so.4
#13 0x419ec53c in khtml::RenderBlock::layoutInlineChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#14 0x419f0de6 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#15 0x41a31a34 in khtml::RenderBlock::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#16 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#17 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#18 0x41a31a34 in khtml::RenderBlock::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#19 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#20 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#21 0x41a37051 in khtml::RenderTableCell::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#22 0x41a16b9e in khtml::RenderTableRow::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#23 0x41a023a4 in khtml::RenderContainer::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#24 0x41a11ee9 in khtml::RenderTable::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#25 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#26 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#27 0x41a31a34 in khtml::RenderBlock::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#28 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#29 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#30 0x41a2e5ce in khtml::RenderBody::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#31 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#32 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#33 0x41a31a34 in khtml::RenderBlock::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#34 0x419f1c1e in khtml::RenderBlock::layoutBlockChildren ()
   from /opt/kde3.3/lib/libkhtml.so.4
#35 0x419f0df9 in khtml::RenderBlock::layoutBlock ()
   from /opt/kde3.3/lib/libkhtml.so.4
#36 0x41a28b49 in khtml::RenderCanvas::layout ()
   from /opt/kde3.3/lib/libkhtml.so.4
#37 0x41955b33 in KHTMLView::layout () from /opt/kde3.3/lib/libkhtml.so.4
#38 0x4195e5cd in KHTMLView::timerEvent () from /opt/kde3.3/lib/libkhtml.so.4
#39 0x40be33cd in QObject::event () from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#40 0x40c10675 in QWidget::event () from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#41 0x40ba0014 in QApplication::internalNotify ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#42 0x40b9fc94 in QApplication::notify ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#43 0x40731d15 in KApplication::notify () from /opt/kde3.3/lib/libkdecore.so.4
#44 0x40b92f32 in QEventLoop::activateTimers ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#45 0x40b5a592 in QEventLoop::processEvents ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#46 0x40bae330 in QEventLoop::enterLoop ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#47 0x40bae277 in QEventLoop::exec () from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#48 0x40ba0186 in QApplication::exec ()
   from /usr/lib/qt-3.3.3/lib/libqt-mt.so.3
#49 0x4151af7e in kdemain () from /opt/kde3.3/lib/libkdeinit_konqueror.so
#50 0x40927806 in kdeinitmain () from /opt/kde3.3/lib/kde3/konqueror.so
#51 0x804d273 in strcpy ()
#52 0x804e47b in strcpy ()
#53 0x804eaf8 in strcpy ()
#54 0x804fe23 in strcpy ()
#55 0x41301c5f in __libc_start_main () from /lib/libc.so.6