Version:           4.2.2 (using KDE 4.2.2)
Compiler:          GCC4.4 
OS:                Linux
Installed from:    Debian testing/unstable Packages

This looks similar to bug 178348, however there are some slight differences (Linux distribution, app versions), so I am posting a new bug report. 

Here is my backtrace: 
Application: Konqueror (konqueror), signal SIGSEGV
[Current thread is 0 (LWP 23142)]

Thread 2 (Thread 0xb1eeab90 (LWP 23148)):
#0  0xb7ef9424 in __kernel_vsyscall ()
#1  0xb60c42e2 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2  0xb7da00b4 in pthread_cond_timedwait () from /lib/i686/cmov/libc.so.6
#3  0xb70047fc in QWaitCondition::wait (this=0x9233aa8, mutex=0x9233aa4, time=30000) at thread/qwaitcondition_unix.cpp:85
#4  0xb6ff9db6 in QThreadPoolThread::run (this=0x8c75470) at concurrent/qthreadpool.cpp:140
#5  0xb700380e in QThreadPrivate::start (arg=0x8c75470) at thread/qthread_unix.cpp:189
#6  0xb60c04e5 in start_thread () from /lib/i686/cmov/libpthread.so.0
#7  0xb7d9121e in clone () from /lib/i686/cmov/libc.so.6

Thread 1 (Thread 0xb5d65710 (LWP 23142)):
[KCrash Handler]
#6  0x092989b3 in ?? ()
#7  0xb3e75ab1 in khtml::RenderBlock::removeChild (this=0x99b296c, oldChild=0x99c8c14) at ../../khtml/rendering/render_block.cpp:617
#8  0xb3e870b5 in khtml::RenderObject::detach (this=0x99c8c14) at ../../khtml/rendering/render_object.h:847
#9  0xb3e9322b in khtml::RenderBox::detach (this=0x99c8c14) at ../../khtml/rendering/render_box.cpp:224
#10 0xb3e9b900 in khtml::RenderFlow::detach (this=0x99c8c14) at ../../khtml/rendering/render_flow.cpp:361
#11 0xb3e911f2 in khtml::RenderBox::detachRemainingChildren (this=0x99b296c) at ../../khtml/rendering/render_box.cpp:242
#12 0xb3e9b89e in khtml::RenderFlow::detach (this=0x99b296c) at ../../khtml/rendering/render_flow.cpp:326
#13 0xb3e9b896 in khtml::RenderFlow::detach (this=0x99b28a4) at ../../khtml/rendering/render_flow.cpp:322
#14 0xb3dcb23c in DOM::NodeImpl::detach (this=0x99c85d0) at ../../khtml/xml/dom_nodeimpl.cpp:971
#15 0xb3dd833b in DOM::ElementImpl::detach (this=0x99c85d0) at ../../khtml/xml/dom_elementimpl.cpp:856
#16 0xb3dd903d in DOM::ElementImpl::recalcStyle (this=0x99c85d0, change=DOM::NodeImpl::Force) at ../../khtml/xml/dom_elementimpl.cpp:930
#17 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99c85d0, ch=DOM::NodeImpl::Force) at ../../khtml/html/html_elementimpl.cpp:269
#18 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x99c7530, change=DOM::NodeImpl::Force) at ../../khtml/xml/dom_elementimpl.cpp:961
#19 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99c7530, ch=DOM::NodeImpl::Force) at ../../khtml/html/html_elementimpl.cpp:269
#20 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x99c6fb8, change=DOM::NodeImpl::Force) at ../../khtml/xml/dom_elementimpl.cpp:961
#21 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99c6fb8, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#22 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x99c3a18, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#23 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99c3a18, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#24 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x99b6180, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#25 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99b6180, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#26 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x99b6aa0, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#27 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x99b6aa0, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#28 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x98eee20, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#29 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x98eee20, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#30 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x956fd38, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#31 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x956fd38, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#32 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x94fcea8, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#33 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x94fcea8, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#34 0xb3dd8f2f in DOM::ElementImpl::recalcStyle (this=0x9295f40, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_elementimpl.cpp:961
#35 0xb3e251a9 in DOM::HTMLElementImpl::recalcStyle (this=0x9295f40, ch=DOM::NodeImpl::NoChange) at ../../khtml/html/html_elementimpl.cpp:269
#36 0xb3dc7dc2 in DOM::DocumentImpl::recalcStyle (this=0x9298998, change=DOM::NodeImpl::NoChange) at ../../khtml/xml/dom_docimpl.cpp:1445
#37 0xb3db3158 in DOM::DocumentImpl::updateRendering (this=0x99b2908) at ../../khtml/xml/dom_docimpl.cpp:1474
#38 0xb3dbea10 in DOM::DocumentImpl::updateDocumentsRendering () at ../../khtml/xml/dom_docimpl.cpp:1487
#39 0xb3fb643c in KJS::Window::afterScriptExecution (this=0xb16a0040) at ../../khtml/ecma/kjs_window.cpp:1288
#40 0xb3fcd67d in KJS::KJSProxyImpl::evaluate (this=0x9256388, filename=
      {static null = {<No data fields>}, static shared_null = {ref = {_q_value = 26077}, alloc = 0, size = 0, data = 0xb71eac1a, clean = 0, simpletext = 0, righttoleft = 0, asciiCache = 0, capacity = 0, reserved = 0, array = {0}}, static shared_empty = {ref = {_q_value = 191}, alloc = 0, size = 0, data = 0xb71eac2e, clean = 0, simpletext = 0, righttoleft = 0, asciiCache = 0, capacity = 0, reserved = 0, array = {0}}, d = 0xbf913058, static codecForCStrings = 0x0}, baseLine=2641, str=@0xbf913288, n=@0xbf9130bc, completion=0xbf913030) at ../../khtml/ecma/kjs_proxy.cpp:170
#41 0xb3d7a96e in KHTMLPart::executeScript (this=0x8d6b188, filename=@0xbf9130d8, baseLine=2641, n=@0xbf9130bc, script=@0xbf913288) at ../../khtml/khtml_part.cpp:1319
#42 0xb3e0d639 in khtml::HTMLTokenizer::scriptExecution (this=0x924d020, str=@0xbf913288, scriptURL=@0xbf913284, baseLine=2641) at ../../khtml/html/htmltokenizer.cpp:501
#43 0xb3e12a64 in khtml::HTMLTokenizer::scriptHandler (this=0x924d020) at ../../khtml/html/htmltokenizer.cpp:454
#44 0xb3e140ed in khtml::HTMLTokenizer::parseSpecial (this=0x924d020, src=@0x924d520) at ../../khtml/html/htmltokenizer.cpp:369
#45 0xb3e15ffd in khtml::HTMLTokenizer::parseTag (this=0x924d020, src=@0x924d520) at ../../khtml/html/htmltokenizer.cpp:1551
#46 0xb3e175de in khtml::HTMLTokenizer::write (this=0x924d020, str=@0xbf913698, appendData=false) at ../../khtml/html/htmltokenizer.cpp:1811
#47 0xb3e11ff8 in khtml::HTMLTokenizer::notifyFinished (this=0x924d020) at ../../khtml/html/htmltokenizer.cpp:2136
#48 0xb3f3b16d in khtml::CachedScript::checkNotify (this=0x9790af0) at ../../khtml/misc/loader.cpp:391
#49 0xb3f3e8cc in khtml::CachedScript::data (this=0x9790af0, buffer=@0x978859c, eof=true) at ../../khtml/misc/loader.cpp:383
#50 0xb3f3e4f2 in khtml::Loader::slotFinished (this=0x8c58da0, job=0x97bb788) at ../../khtml/misc/loader.cpp:1409
#51 0xb3f44737 in khtml::Loader::qt_metacall (this=0x8c58da0, _c=QMetaObject::InvokeMetaMethod, _id=3, _a=0xbf91392c) at ./loader.moc:129
#52 0xb710cb98 in QMetaObject::activate (sender=0x97bb788, from_signal_index=7, to_signal_index=7, argv=0xbf91392c) at kernel/qobject.cpp:3120
#53 0xb710d822 in QMetaObject::activate (sender=0x97bb788, m=0xb7483c88, local_signal_index=3, argv=0xbf91392c) at kernel/qobject.cpp:3194
#54 0xb7336073 in KJob::result (this=0x97bb788, _t1=0x97bb788) at ./kjob.moc:186
#55 0xb7336519 in KJob::emitResult (this=0x97bb788) at ../../kdecore/jobs/kjob.cpp:294
#56 0xb7915da5 in KIO::SimpleJob::slotFinished (this=0x97bb788) at ../../kio/kio/job.cpp:489
#57 0xb7917013 in KIO::TransferJob::slotFinished (this=0x97bb788) at ../../kio/kio/job.cpp:966
#58 0xb79180fb in KIO::TransferJob::qt_metacall (this=0x97bb788, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbf913b68) at ./jobclasses.moc:336
#59 0xb710cb98 in QMetaObject::activate (sender=0x8e1e7b8, from_signal_index=8, to_signal_index=8, argv=0x0) at kernel/qobject.cpp:3120
#60 0xb710d822 in QMetaObject::activate (sender=0x8e1e7b8, m=0xb7ac0ae4, local_signal_index=4, argv=0x0) at kernel/qobject.cpp:3194
#61 0xb79d50e7 in KIO::SlaveInterface::finished (this=0x8e1e7b8) at ./slaveinterface.moc:163
#62 0xb79d8e27 in KIO::SlaveInterface::dispatch (this=0x8e1e7b8, _cmd=104, rawdata=@0xbf913d34) at ../../kio/kio/slaveinterface.cpp:175
#63 0xb79d55c7 in KIO::SlaveInterface::dispatch (this=0x8e1e7b8) at ../../kio/kio/slaveinterface.cpp:91
#64 0xb79c597d in KIO::Slave::gotInput (this=0x8e1e7b8) at ../../kio/kio/slave.cpp:322
#65 0xb79c7ed3 in KIO::Slave::qt_metacall (this=0x8e1e7b8, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbf913e48) at ./slave.moc:75
#66 0xb710cb98 in QMetaObject::activate (sender=0x8ddb590, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3120
#67 0xb710d822 in QMetaObject::activate (sender=0x8ddb590, m=0xb7abd5c0, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3194
#68 0xb78dc1a7 in KIO::Connection::readyRead (this=0x8ddb590) at ./connection.moc:84
#69 0xb78ddb03 in KIO::ConnectionPrivate::dequeue (this=0x8c1b168) at ../../kio/kio/connection.cpp:82
#70 0xb78ddee6 in KIO::Connection::qt_metacall (this=0x8ddb590, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x97bf768) at ./connection.moc:72
#71 0xb71057eb in QMetaCallEvent::placeMetaCall (this=0x91b75e0, object=0x8ddb590) at kernel/qobject.cpp:489
#72 0xb7107290 in QObject::event (this=0x8ddb590, e=0x91b75e0) at kernel/qobject.cpp:1118
#73 0xb66fd7bc in QApplicationPrivate::notify_helper (this=0x8873bd0, receiver=0x8ddb590, e=0x91b75e0) at kernel/qapplication.cpp:4057
#74 0xb6705ace in QApplication::notify (this=0xbf9147a8, receiver=0x8ddb590, e=0x91b75e0) at kernel/qapplication.cpp:3604
#75 0xb7659b7d in KApplication::notify (this=0xbf9147a8, receiver=0x8ddb590, event=0x91b75e0) at ../../kdeui/kernel/kapplication.cpp:307
#76 0xb70f6a2b in QCoreApplication::notifyInternal (this=0xbf9147a8, receiver=0x8ddb590, event=0x91b75e0) at kernel/qcoreapplication.cpp:610
#77 0xb70f7685 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x885b6e8) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#78 0xb70f787d in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1140
#79 0xb712274f in postEventSourceDispatch (s=0x8875f10) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#80 0xb610c848 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#81 0xb610fdab in ?? () from /usr/lib/libglib-2.0.so.0
#82 0x08875e90 in ?? ()
#83 0x00000000 in ?? ()

How to reproduce: Load at least 5-6 sites with a lot of information. In my case, that was: anidb.net, several tabs of it open; kaldata.com/forums, also 3 tabs from different links; ruby-doc.org . 

Default behaviour: crash. Expected behaviour: load sites without crash, (probably) slowdown (as in versions of konqueror in KDE3) .