#11 0x00007ff8b0a46367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#12 0x00007ff8b0a495c3 in Bespin::Style::updateBlurRegions() const () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so

Can you reproduce this crash if you use some other style, e.g. oxygen?

I think not

Here another backtrace very similar to the previous one:

Application: Konqueror (kdeinit4), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f5acc6e27c0 (LWP 2722))]

Thread 10 (Thread 0x7f5ab0054700 (LWP 2723)):
#0  0x00007f5ac70da359 in g_mutex_get_impl (mutex=0x7f5aa80009a0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:121
#1  0x00007f5ac70da5e9 in g_mutex_unlock (mutex=mutex@entry=0x7f5aa80009a0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:229
#2  0x00007f5ac709b30e in g_main_context_iteration (context=0x7f5aa80009a0, may_block=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3763
#3  0x00007f5acb388036 in QEventDispatcherGlib::processEvents (this=0x7f5aa80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f5acb35838f in QEventLoop::processEvents (this=this@entry=0x7f5ab0053d90, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f5acb358618 in QEventLoop::exec (this=this@entry=0x7f5ab0053d90, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f5acb25a410 in QThread::exec (this=this@entry=0xa0a390) at thread/qthread.cpp:542
#7  0x00007f5ac28b1cde in KIO::NameLookUpThread::run (this=0xa0a390) at ../../kio/kio/hostinfo.cpp:226
#8  0x00007f5acb25cbec in QThreadPrivate::start (arg=0xa0a390) at thread/qthread_unix.cpp:338
#9  0x00007f5ac776ff8e in start_thread (arg=0x7f5ab0054700) at pthread_create.c:311
#10 0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 9 (Thread 0x7f5a9104a700 (LWP 2793)):
#0  0x00007f5ac70da979 in g_private_get (key=key@entry=0x7f5ac734cba0 <g_thread_specific_private>) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:1013
#1  0x00007f5ac70bf390 in g_thread_self () at /build/buildd/glib2.0-2.36.0/./glib/gthread.c:993
#2  0x00007f5ac709a33e in g_main_context_acquire (context=0x7f5a8c0009a0) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3110
#3  0x00007f5ac709b0b4 in g_main_context_iterate (context=context@entry=0x7f5a8c0009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3651
#4  0x00007f5ac709b304 in g_main_context_iteration (context=0x7f5a8c0009a0, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007f5acb388036 in QEventDispatcherGlib::processEvents (this=0x7f5a8c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007f5acb35838f in QEventLoop::processEvents (this=this@entry=0x7f5a91049d90, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f5acb358618 in QEventLoop::exec (this=this@entry=0x7f5a91049d90, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f5acb25a410 in QThread::exec (this=this@entry=0x6e861c0) at thread/qthread.cpp:542
#9  0x00007f5acb339edf in QInotifyFileSystemWatcherEngine::run (this=0x6e861c0) at io/qfilesystemwatcher_inotify.cpp:256
#10 0x00007f5acb25cbec in QThreadPrivate::start (arg=0x6e861c0) at thread/qthread_unix.cpp:338
#11 0x00007f5ac776ff8e in start_thread (arg=0x7f5a9104a700) at pthread_create.c:311
#12 0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 8 (Thread 0x7f5aaf853700 (LWP 3590)):
#0  0x00007f5ac70da359 in g_mutex_get_impl (mutex=0x7f5aa000c790) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:121
#1  0x00007f5ac70da5e9 in g_mutex_unlock (mutex=mutex@entry=0x7f5aa000c790) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:229
#2  0x00007f5ac709b1d1 in g_main_context_poll (n_fds=1, fds=0x7f5aa0009b90, timeout=-1, context=0x7f5aa000c790, priority=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3994
#3  g_main_context_iterate (context=context@entry=0x7f5aa000c790, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3696
#4  0x00007f5ac709b304 in g_main_context_iteration (context=0x7f5aa000c790, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007f5acb388036 in QEventDispatcherGlib::processEvents (this=0x7f5aa00051d0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007f5acb35838f in QEventLoop::processEvents (this=this@entry=0x7f5aaf852d90, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f5acb358618 in QEventLoop::exec (this=this@entry=0x7f5aaf852d90, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f5acb25a410 in QThread::exec (this=this@entry=0xfae6390) at thread/qthread.cpp:542
#9  0x00007f5acb339edf in QInotifyFileSystemWatcherEngine::run (this=0xfae6390) at io/qfilesystemwatcher_inotify.cpp:256
#10 0x00007f5acb25cbec in QThreadPrivate::start (arg=0xfae6390) at thread/qthread_unix.cpp:338
#11 0x00007f5ac776ff8e in start_thread (arg=0x7f5aaf853700) at pthread_create.c:311
#12 0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 7 (Thread 0x7f5aa6013700 (LWP 3611)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f5abf78b585 in WTF::TCMalloc_PageHeap::scavengerThread() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f5abf78b5d9 in WTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f5ac776ff8e in start_thread (arg=0x7f5aa6013700) at pthread_create.c:311
#4  0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 6 (Thread 0x7f5aa6814700 (LWP 3613)):
#0  __pthread_mutex_unlock_usercnt (mutex=0x7f5a98001b10, decr=1) at pthread_mutex_unlock.c:69
#1  0x00007f5ac70da5f1 in g_mutex_unlock (mutex=mutex@entry=0x7f5a98002340) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:229
#2  0x00007f5ac709ac61 in g_main_context_check (context=context@entry=0x7f5a98002340, max_priority=2147483647, fds=fds@entry=0x7f5a980047c0, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3543
#3  0x00007f5ac709b175 in g_main_context_iterate (context=context@entry=0x7f5a98002340, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3698
#4  0x00007f5ac709b304 in g_main_context_iteration (context=0x7f5a98002340, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007f5acb388036 in QEventDispatcherGlib::processEvents (this=0x7f5a98001f00, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007f5acb35838f in QEventLoop::processEvents (this=this@entry=0x7f5aa6813dc0, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f5acb358618 in QEventLoop::exec (this=this@entry=0x7f5aa6813dc0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f5acb25a410 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:542
#9  0x00007f5acb25cbec in QThreadPrivate::start (arg=0x109e4560) at thread/qthread_unix.cpp:338
#10 0x00007f5ac776ff8e in start_thread (arg=0x7f5aa6814700) at pthread_create.c:311
#11 0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 5 (Thread 0x7f5a8b2be700 (LWP 3614)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f5abf4d1a09 in JSC::BlockAllocator::blockFreeingThreadMain() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f5abf7b9cee in WTF::wtfThreadEntryPoint(void*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f5ac776ff8e in start_thread (arg=0x7f5a8b2be700) at pthread_create.c:311
#4  0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 4 (Thread 0x7f5a3ae8a700 (LWP 3636)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f5a3aeabf33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007f5ac776ff8e in start_thread (arg=0x7f5a3ae8a700) at pthread_create.c:311
#3  0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 3 (Thread 0x7f5a3a689700 (LWP 3637)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f5a3aeabf33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007f5ac776ff8e in start_thread (arg=0x7f5a3a689700) at pthread_create.c:311
#3  0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 2 (Thread 0x7f5a39e88700 (LWP 3638)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f5a3aeabf33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007f5ac776ff8e in start_thread (arg=0x7f5a39e88700) at pthread_create.c:311
#3  0x00007f5ac9f62a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 1 (Thread 0x7f5acc6e27c0 (LWP 2722)):
[KCrash Handler]
#6  0x00007f5ab5996345 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#7  0x00007f5ab5996367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#8  0x00007f5ab5996367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#9  0x00007f5ab5996367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#10 0x00007f5ab5996367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#11 0x00007f5ab59995c3 in Bespin::Style::updateBlurRegions() const () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#12 0x00007f5acb36e0ef in QMetaObject::activate (sender=sender@entry=0x1f9ff010, m=m@entry=0x7f5acb6b1d80 <QSingleShotTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#13 0x00007f5acb376e70 in QSingleShotTimer::timeout (this=this@entry=0x1f9ff010) at .moc/release-shared/qtimer.moc:97
#14 0x00007f5acb376e8f in QSingleShotTimer::timerEvent (this=0x1f9ff010) at kernel/qtimer.cpp:317
#15 0x00007f5acb3733ec in QObject::event (this=0x1f9ff010, e=<optimized out>) at kernel/qobject.cpp:1156
#16 0x00007f5aca6ff8ec in QApplicationPrivate::notify_helper (this=this@entry=0x74e9e0, receiver=receiver@entry=0x1f9ff010, e=e@entry=0x7fff7188b720) at kernel/qapplication.cpp:4567
#17 0x00007f5aca70225b in QApplication::notify (this=this@entry=0x7fff7188e830, receiver=receiver@entry=0x1f9ff010, e=e@entry=0x7fff7188b720) at kernel/qapplication.cpp:4428
#18 0x00007f5acc0dc1a6 in KApplication::notify (this=0x7fff7188e830, receiver=0x1f9ff010, event=0x7fff7188b720) at ../../kdeui/kernel/kapplication.cpp:311
#19 0x00007f5acb35963e in QCoreApplication::notifyInternal (this=0x7fff7188e830, receiver=0x1f9ff010, event=event@entry=0x7fff7188b720) at kernel/qcoreapplication.cpp:946
#20 0x00007f5acb38ab72 in sendEvent (event=0x7fff7188b720, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#21 QTimerInfoList::activateTimers (this=this@entry=0x7500d0) at kernel/qeventdispatcher_unix.cpp:622
#22 0x00007f5acb3879a4 in timerSourceDispatch (source=0x750070) at kernel/qeventdispatcher_glib.cpp:186
#23 timerSourceDispatch (source=source@entry=0x750070) at kernel/qeventdispatcher_glib.cpp:180
#24 0x00007f5ac709af05 in g_main_dispatch (context=0x74ee40) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3054
#25 g_main_context_dispatch (context=context@entry=0x74ee40) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3630
#26 0x00007f5ac709b248 in g_main_context_iterate (context=context@entry=0x74ee40, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3701
#27 0x00007f5ac709b304 in g_main_context_iteration (context=0x74ee40, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#28 0x00007f5acb388016 in QEventDispatcherGlib::processEvents (this=0x672670, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#29 0x00007f5aca7a513e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#30 0x00007f5acb35838f in QEventLoop::processEvents (this=this@entry=0x7fff7188b990, flags=...) at kernel/qeventloop.cpp:149
#31 0x00007f5acb358618 in QEventLoop::exec (this=this@entry=0x7fff7188b990, flags=...) at kernel/qeventloop.cpp:204
#32 0x00007f5ac287e666 in KIO::NetAccess::enter_loop (this=this@entry=0x7fff7188b9f0) at ../../kio/kio/netaccess.cpp:509
#33 0x00007f5ac287e7fc in KIO::NetAccess::synchronousRunInternal (this=this@entry=0x7fff7188b9f0, job=job@entry=0x36f81f0, window=window@entry=0x0, data=data@entry=0x7fff7188bb00, finalURL=finalURL@entry=0x7fff7188bbe0, metaData=metaData@entry=0x7fff7188bab0) at ../../kio/kio/netaccess.cpp:494
#34 0x00007f5ac287e8a5 in KIO::NetAccess::synchronousRun (job=job@entry=0x36f81f0, window=0x0, data=data@entry=0x7fff7188bb00, finalURL=finalURL@entry=0x7fff7188bbe0, metaData=metaData@entry=0x7fff7188bab0) at ../../kio/kio/netaccess.cpp:284
#35 0x00007f5ac27cd780 in KIO::AccessManager::createRequest (this=this@entry=0xd924660, op=op@entry=QNetworkAccessManager::PostOperation, req=..., outgoingData=outgoingData@entry=0x1fed9e0) at ../../kio/kio/accessmanager.cpp:330
#36 0x00007f5a7f2cef60 in KDEPrivate::MyNetworkAccessManager::createRequest (this=0xd924660, op=QNetworkAccessManager::PostOperation, req=..., outgoingData=0x1fed9e0) at ../../src/networkaccessmanager.cpp:91
#37 0x00007f5ac9266a25 in QNetworkAccessManager::post (this=0xd924660, request=..., data=<optimized out>) at access/qnetworkaccessmanager.cpp:617
#38 0x00007f5abec931ac in WebCore::QNetworkReplyHandler::sendNetworkRequest(QNetworkAccessManager*, WebCore::ResourceRequest const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#39 0x00007f5abec934b9 in WebCore::QNetworkReplyHandler::start() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#40 0x00007f5abec91681 in WebCore::QNetworkReplyHandlerCallQueue::flush() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#41 0x00007f5abec8bdf1 in WebCore::ResourceHandle::loadResourceSynchronously(WebCore::NetworkingContext*, WebCore::ResourceRequest const&, WebCore::StoredCredentials, WebCore::ResourceError&, WebCore::ResourceResponse&, WTF::Vector<char, 0ul>&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#42 0x00007f5abe918149 in WebCore::FrameLoader::loadResourceSynchronously(WebCore::ResourceRequest const&, WebCore::StoredCredentials, WebCore::ResourceError&, WebCore::ResourceResponse&, WTF::Vector<char, 0ul>&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#43 0x00007f5abe8fe98b in WebCore::DocumentThreadableLoader::loadRequest(WebCore::ResourceRequest const&, WebCore::SecurityCheckPolicy) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#44 0x00007f5abe901d88 in WebCore::DocumentThreadableLoader::DocumentThreadableLoader(WebCore::Document*, WebCore::ThreadableLoaderClient*, WebCore::DocumentThreadableLoader::BlockingBehavior, WebCore::ResourceRequest const&, WebCore::ThreadableLoaderOptions const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#45 0x00007f5abe901fec in WebCore::DocumentThreadableLoader::loadResourceSynchronously(WebCore::Document*, WebCore::ResourceRequest const&, WebCore::ThreadableLoaderClient&, WebCore::ThreadableLoaderOptions const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#46 0x00007f5abec4aeef in WebCore::XMLHttpRequest::createRequest(int&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#47 0x00007f5abec4feda in WebCore::XMLHttpRequest::send(WTF::String const&, int&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#48 0x00007f5abe3dcf99 in WebCore::JSXMLHttpRequest::send(JSC::ExecState*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#49 0x00007f5abf219dcb in WebCore::jsXMLHttpRequestPrototypeFunctionSend(JSC::ExecState*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#50 0x00007f5a3f193265 in ?? ()
#51 0x0000000000000002 in ?? ()
#52 0x00007f5a3f2e5c31 in ?? ()
#53 0x0000000000000001 in ?? ()
#54 0x00007f5a2b9d9ee0 in ?? ()
#55 0x00007f5a276ba5c0 in ?? ()
#56 0x00007f5a3be142c0 in ?? ()
#57 0x00007f5a3f2b35ed in ?? ()
#58 0x000000057188e830 in ?? ()
#59 0x00007f5a3d3dc800 in ?? ()
#60 0x00007f5a3e0bf040 in ?? ()
#61 0x00007f5a7f198110 in ?? ()
#62 0x00007f5a3f3633a0 in ?? ()
#63 0x00007f5a7f198110 in ?? ()
#64 0x00007f5a3e0bf360 in ?? ()
#65 0x0000000000000000 in ?? ()

I got this by closing Konqueror.

And, I have been thinking and this kind of crashes always occurs when I shift from KHTML to Webkit in twitter, does not matter if I am using Bespin or Oxygen, I think it could be related to Webkit.

This backtrace of this crash is in the theme engine you're using, bespin which Konqueror can do nothing about? Can you post the backtrace for the crash you get when you switch from KHTML to WebKit in twitter? You said that one crashes regardless of whether you using Bespin or Oxygen, right?

As quick workaround, exclude "konqueror" from ARGB windows in "bespin config"

Unfortunately the backtraece lacks line numbers, but what the function does is to recursively parse children of the window and for ::isWidgetType() ones check visibility, autoFillBackground, background color, WA_OpaquePaintEvent and whether they're QScrollBar or QProgressBar and add them or their mask to a region.

-> Either there's a dangeling or a nullpointer in QObject::children()
(the delayed update is protected by a weakpointer on the window and we're too deep in the recursion)

Is facebook mandatory or did you encounter this when changing the render engine on other pages as well?
Can you reproduce it by

   export QT_NO_GLIB=1
   konqueror

as well (notice that w/o the glib dispatcher eg. flash will likely stop to work)

Notice that QtCurve and oxygen-transparent may have similar code.

(In reply to comment #4)
>Can you post the backtrace for the crash you get when you switch from KHTML to WebKit in twitter?

I can't, that does not occur. It occurs, sometimes, from Webkit to KHTML

(In reply to comment #4)
> You said that one crashes regardless of whether you using Bespin or Oxygen, right?

Yes, but now, I have noticed another thing: when I am in my timeline of twitter, using Besping not Oxygen as theme, with Webkit as engine, and in the same tab of Konqueror I type in the search bar another direction of twitter, for example, twitter.com/user, Konqueror crashes. It always occurs, and the backtrace is very similar. Maybe, really all this is related to Bespin:

Application: Konqueror (kdeinit4), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7ff3ffd417c0 (LWP 4522))]

Thread 9 (Thread 0x7ff3e2afa700 (LWP 4524)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ff3f2deb585 in WTF::TCMalloc_PageHeap::scavengerThread() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007ff3f2deb5d9 in WTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007ff3fadcff8e in start_thread (arg=0x7ff3e2afa700) at pthread_create.c:311
#4  0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 8 (Thread 0x7ff39db60700 (LWP 4525)):
#0  timerSourcePrepareHelper (src=0x7ff398002800, timeout=0x7ff39db5fbc4) at kernel/qeventdispatcher_glib.cpp:136
#1  0x00007ff3fe9e7845 in timerSourcePrepare (source=<optimized out>, timeout=timeout@entry=0x7ff39db5fbc4) at kernel/qeventdispatcher_glib.cpp:169
#2  0x00007ff3fa6fa900 in g_main_context_prepare (context=context@entry=0x7ff3980009a0, priority=priority@entry=0x7ff39db5fc38) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3328
#3  0x00007ff3fa6fb0fe in g_main_context_iterate (context=context@entry=0x7ff3980009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3681
#4  0x00007ff3fa6fb304 in g_main_context_iteration (context=0x7ff3980009a0, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007ff3fe9e8036 in QEventDispatcherGlib::processEvents (this=0x7ff3980008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007ff3fe9b838f in QEventLoop::processEvents (this=this@entry=0x7ff39db5fd90, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007ff3fe9b8618 in QEventLoop::exec (this=this@entry=0x7ff39db5fd90, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007ff3fe8ba410 in QThread::exec (this=this@entry=0x424a160) at thread/qthread.cpp:542
#9  0x00007ff3fe999edf in QInotifyFileSystemWatcherEngine::run (this=0x424a160) at io/qfilesystemwatcher_inotify.cpp:256
#10 0x00007ff3fe8bcbec in QThreadPrivate::start (arg=0x424a160) at thread/qthread_unix.cpp:338
#11 0x00007ff3fadcff8e in start_thread (arg=0x7ff39db60700) at pthread_create.c:311
#12 0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 7 (Thread 0x7ff397fff700 (LWP 4527)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ff3f2b31a09 in JSC::BlockAllocator::blockFreeingThreadMain() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007ff3f2e19cee in WTF::wtfThreadEntryPoint(void*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007ff3fadcff8e in start_thread (arg=0x7ff397fff700) at pthread_create.c:311
#4  0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 6 (Thread 0x7ff396ffd700 (LWP 4531)):
#0  0x00007ff3fa73a359 in g_mutex_get_impl (mutex=0x7ff38c0009a0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:121
#1  0x00007ff3fa73a5b9 in g_mutex_lock (mutex=mutex@entry=0x7ff38c0009a0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:210
#2  0x00007ff3fa6fade6 in g_main_context_dispatch (context=context@entry=0x7ff38c0009a0) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3626
#3  0x00007ff3fa6fb248 in g_main_context_iterate (context=context@entry=0x7ff38c0009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3701
#4  0x00007ff3fa6fb304 in g_main_context_iteration (context=0x7ff38c0009a0, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007ff3fe9e8036 in QEventDispatcherGlib::processEvents (this=0x7ff38c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007ff3fe9b838f in QEventLoop::processEvents (this=this@entry=0x7ff396ffcdc0, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007ff3fe9b8618 in QEventLoop::exec (this=this@entry=0x7ff396ffcdc0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007ff3fe8ba410 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:542
#9  0x00007ff3fe8bcbec in QThreadPrivate::start (arg=0x1f4bda0) at thread/qthread_unix.cpp:338
#10 0x00007ff3fadcff8e in start_thread (arg=0x7ff396ffd700) at pthread_create.c:311
#11 0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 5 (Thread 0x7ff395bda700 (LWP 4611)):
#0  0x00007ff3fa73a345 in g_mutex_get_impl (mutex=0x7ff3800008c0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:120
#1  0x00007ff3fa73a5b9 in g_mutex_lock (mutex=mutex@entry=0x7ff3800008c0) at /build/buildd/glib2.0-2.36.0/./glib/gthread-posix.c:210
#2  0x00007ff3fa6fa90b in g_main_context_prepare (context=context@entry=0x7ff3800008c0, priority=priority@entry=0x7ff395bd9c38) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3330
#3  0x00007ff3fa6fb0fe in g_main_context_iterate (context=context@entry=0x7ff3800008c0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3681
#4  0x00007ff3fa6fb304 in g_main_context_iteration (context=0x7ff3800008c0, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#5  0x00007ff3fe9e8036 in QEventDispatcherGlib::processEvents (this=0x7ff3800041d0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007ff3fe9b838f in QEventLoop::processEvents (this=this@entry=0x7ff395bd9d90, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007ff3fe9b8618 in QEventLoop::exec (this=this@entry=0x7ff395bd9d90, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007ff3fe8ba410 in QThread::exec (this=this@entry=0x4710cc0) at thread/qthread.cpp:542
#9  0x00007ff3f5f11cde in KIO::NameLookUpThread::run (this=0x4710cc0) at ../../kio/kio/hostinfo.cpp:226
#10 0x00007ff3fe8bcbec in QThreadPrivate::start (arg=0x4710cc0) at thread/qthread_unix.cpp:338
#11 0x00007ff3fadcff8e in start_thread (arg=0x7ff395bda700) at pthread_create.c:311
#12 0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 4 (Thread 0x7ff37536e700 (LWP 4649)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ff37538ff33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007ff3fadcff8e in start_thread (arg=0x7ff37536e700) at pthread_create.c:311
#3  0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 3 (Thread 0x7ff374b6d700 (LWP 4650)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ff37538ff33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007ff3fadcff8e in start_thread (arg=0x7ff374b6d700) at pthread_create.c:311
#3  0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 2 (Thread 0x7ff36ffff700 (LWP 4651)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ff37538ff33 in queue_processor(void*) () from /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
#2  0x00007ff3fadcff8e in start_thread (arg=0x7ff36ffff700) at pthread_create.c:311
#3  0x00007ff3fd5c2a0d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 1 (Thread 0x7ff3ffd417c0 (LWP 4522)):
[KCrash Handler]
#6  0x00007ff3e8ff6345 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#7  0x00007ff3e8ff6367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#8  0x00007ff3e8ff6367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#9  0x00007ff3e8ff6367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#10 0x00007ff3e8ff6367 in detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#11 0x00007ff3e8ff95c3 in Bespin::Style::updateBlurRegions() const () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so
#12 0x00007ff3fe9ce0ef in QMetaObject::activate (sender=sender@entry=0x9c34850, m=m@entry=0x7ff3fed11d80 <QSingleShotTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#13 0x00007ff3fe9d6e70 in QSingleShotTimer::timeout (this=this@entry=0x9c34850) at .moc/release-shared/qtimer.moc:97
#14 0x00007ff3fe9d6e8f in QSingleShotTimer::timerEvent (this=0x9c34850) at kernel/qtimer.cpp:317
#15 0x00007ff3fe9d33ec in QObject::event (this=0x9c34850, e=<optimized out>) at kernel/qobject.cpp:1156
#16 0x00007ff3fdd5f8ec in QApplicationPrivate::notify_helper (this=this@entry=0x18e7520, receiver=receiver@entry=0x9c34850, e=e@entry=0x7fffb4b9e820) at kernel/qapplication.cpp:4567
#17 0x00007ff3fdd6225b in QApplication::notify (this=this@entry=0x7fffb4ba1aa0, receiver=receiver@entry=0x9c34850, e=e@entry=0x7fffb4b9e820) at kernel/qapplication.cpp:4428
#18 0x00007ff3ff73c1a6 in KApplication::notify (this=0x7fffb4ba1aa0, receiver=0x9c34850, event=0x7fffb4b9e820) at ../../kdeui/kernel/kapplication.cpp:311
#19 0x00007ff3fe9b963e in QCoreApplication::notifyInternal (this=0x7fffb4ba1aa0, receiver=0x9c34850, event=event@entry=0x7fffb4b9e820) at kernel/qcoreapplication.cpp:946
#20 0x00007ff3fe9eab72 in sendEvent (event=0x7fffb4b9e820, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#21 QTimerInfoList::activateTimers (this=this@entry=0x18e7bb0) at kernel/qeventdispatcher_unix.cpp:622
#22 0x00007ff3fe9e79a4 in timerSourceDispatch (source=0x18e7b50) at kernel/qeventdispatcher_glib.cpp:186
#23 timerSourceDispatch (source=source@entry=0x18e7b50) at kernel/qeventdispatcher_glib.cpp:180
#24 0x00007ff3fa6faf05 in g_main_dispatch (context=0x18e7930) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3054
#25 g_main_context_dispatch (context=context@entry=0x18e7930) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3630
#26 0x00007ff3fa6fb248 in g_main_context_iterate (context=context@entry=0x18e7930, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3701
#27 0x00007ff3fa6fb304 in g_main_context_iteration (context=0x18e7930, may_block=1) at /build/buildd/glib2.0-2.36.0/./glib/gmain.c:3762
#28 0x00007ff3fe9e8016 in QEventDispatcherGlib::processEvents (this=0x180b670, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#29 0x00007ff3fde0513e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#30 0x00007ff3fe9b838f in QEventLoop::processEvents (this=this@entry=0x7fffb4b9ea90, flags=...) at kernel/qeventloop.cpp:149
#31 0x00007ff3fe9b8618 in QEventLoop::exec (this=this@entry=0x7fffb4b9ea90, flags=...) at kernel/qeventloop.cpp:204
#32 0x00007ff3f5ede666 in KIO::NetAccess::enter_loop (this=this@entry=0x7fffb4b9eaf0) at ../../kio/kio/netaccess.cpp:509
#33 0x00007ff3f5ede7fc in KIO::NetAccess::synchronousRunInternal (this=this@entry=0x7fffb4b9eaf0, job=job@entry=0x6ea7ee0, window=window@entry=0x1bbf8f0, data=data@entry=0x7fffb4b9ec00, finalURL=finalURL@entry=0x7fffb4b9ece0, metaData=metaData@entry=0x7fffb4b9ebb0) at ../../kio/kio/netaccess.cpp:494
#34 0x00007ff3f5ede8a5 in KIO::NetAccess::synchronousRun (job=job@entry=0x6ea7ee0, window=0x1bbf8f0, data=data@entry=0x7fffb4b9ec00, finalURL=finalURL@entry=0x7fffb4b9ece0, metaData=metaData@entry=0x7fffb4b9ebb0) at ../../kio/kio/netaccess.cpp:284
#35 0x00007ff3f5e2d780 in KIO::AccessManager::createRequest (this=this@entry=0xdb625e0, op=op@entry=QNetworkAccessManager::PostOperation, req=..., outgoingData=outgoingData@entry=0xab6d9a0) at ../../kio/kio/accessmanager.cpp:330
#36 0x00007ff3e2b3df60 in KDEPrivate::MyNetworkAccessManager::createRequest (this=0xdb625e0, op=QNetworkAccessManager::PostOperation, req=..., outgoingData=0xab6d9a0) at ../../src/networkaccessmanager.cpp:91
#37 0x00007ff3fc8c6a25 in QNetworkAccessManager::post (this=0xdb625e0, request=..., data=<optimized out>) at access/qnetworkaccessmanager.cpp:617
#38 0x00007ff3f22f31ac in WebCore::QNetworkReplyHandler::sendNetworkRequest(QNetworkAccessManager*, WebCore::ResourceRequest const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#39 0x00007ff3f22f34b9 in WebCore::QNetworkReplyHandler::start() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#40 0x00007ff3f22f1681 in WebCore::QNetworkReplyHandlerCallQueue::flush() () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#41 0x00007ff3f22ebdf1 in WebCore::ResourceHandle::loadResourceSynchronously(WebCore::NetworkingContext*, WebCore::ResourceRequest const&, WebCore::StoredCredentials, WebCore::ResourceError&, WebCore::ResourceResponse&, WTF::Vector<char, 0ul>&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#42 0x00007ff3f1f78149 in WebCore::FrameLoader::loadResourceSynchronously(WebCore::ResourceRequest const&, WebCore::StoredCredentials, WebCore::ResourceError&, WebCore::ResourceResponse&, WTF::Vector<char, 0ul>&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#43 0x00007ff3f1f5e98b in WebCore::DocumentThreadableLoader::loadRequest(WebCore::ResourceRequest const&, WebCore::SecurityCheckPolicy) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#44 0x00007ff3f1f61d88 in WebCore::DocumentThreadableLoader::DocumentThreadableLoader(WebCore::Document*, WebCore::ThreadableLoaderClient*, WebCore::DocumentThreadableLoader::BlockingBehavior, WebCore::ResourceRequest const&, WebCore::ThreadableLoaderOptions const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#45 0x00007ff3f1f61fec in WebCore::DocumentThreadableLoader::loadResourceSynchronously(WebCore::Document*, WebCore::ResourceRequest const&, WebCore::ThreadableLoaderClient&, WebCore::ThreadableLoaderOptions const&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#46 0x00007ff3f22aaeef in WebCore::XMLHttpRequest::createRequest(int&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#47 0x00007ff3f22afeda in WebCore::XMLHttpRequest::send(WTF::String const&, int&) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#48 0x00007ff3f1a3cf99 in WebCore::JSXMLHttpRequest::send(JSC::ExecState*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#49 0x00007ff3f2879dcb in WebCore::jsXMLHttpRequestPrototypeFunctionSend(JSC::ExecState*) () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#50 0x00007ff3a21e1265 in ?? ()
#51 0x0000000000000002 in ?? ()
#52 0x00007ff3a2624170 in ?? ()
#53 0x00007fffb4b9fdc0 in ?? ()
#54 0x00007ff35cd7c1c0 in ?? ()
#55 0x00007ff360032858 in ?? ()
#56 0x00007ff3600f0aa0 in ?? ()
#57 0x00007ff3a25883e2 in ?? ()
#58 0x00007fffb4ba1aa0 in ?? ()
#59 0x000000000f7619c0 in ?? ()
#60 0x00007ff39c0e7040 in ?? ()
#61 0x00007ff3e225c390 in ?? ()
#62 0x00007ff3a2595520 in ?? ()
#63 0x00007ff3e225c390 in ?? ()
#64 0x00007ff39c0e7360 in ?? ()
#65 0x0000000000000000 in ?? ()

As I said previously, this crash, I can confirm only happens with Bespin.

I get crashes for "neither" (was on facebook & twitter but have no account for either and will certainly not create one)
Can you compile bespin from svn or does Ubuntu ship debug packages for bespin?

I have compiled bespin from SVN, I don't know how to determinate the revision...

Created attachment 84457 [details]
Debug output for Bespin

"svn info"

Splendid, for that will allow you to add the attached patch to tell us where things crash.
Notice that it will print a lot of information to konsole - or .xsession-errors so i suggest to compile it in, run 

konqueror > bespin.debug 2>&1

make it crash and attach the bespin.debug file (you'll eventually have to compress it)

OK 

I have make this:

Applied patch to bespin.cpp
Ran: ./configure
cd build
make
sudo make install

If I have made a mistake, please let me know. Keep in mind, I am just a "desktop" user.

Next, I have ran:

konqueror > bespin.debug 2>&1

The file is attached (bespin.debug)

Also, I have noticed that the file configure of bespin svn, in line 64 has the command: ccmake, it obviously is wrong and gives an error by running ./configure:

$ ./configure
==================== Bespin interactive configuration ====================

    Seems you have cmake.
    In addition to the style, you can have a KWin decoration,
    a mac-like menu plasmoid and config plugins IFF you have KDE....

--> Do you want to compile with KDE support? [Y/n]
-- Found Qt-Version 4.8.4 (using /usr/lib/x86_64-linux-gnu/qt4/bin/qmake)
-- Found X11: /usr/lib/x86_64-linux-gnu/libX11.so
-- Found KDE 4.10 include dir: /usr/include
-- Found KDE 4.10 library dir: /usr/lib
-- Found the KDE4 kconfig_compiler preprocessor: /usr/bin/kconfig_compiler
-- Found automoc4: /usr/bin/automoc4
-- WARNING: *** ARGB windows are experimental, performance might suffer ***
-- WARNING: *** Variable shadow pixmap sizes will cause glitches on KWin < 4.7.4 and OpenGL ***
-- Found X11: /usr/lib/x86_64-linux-gnu/libX11.so
-- INFO: XRender was found - kwin deco & FX via GPU available!
-- QtDbus available - Style will support XBar
-- KWin headers found
-- Configuring done
-- Generating done
-- Build files have been written to: /home/gatoso/Paquetes/cloudcity-code/build

Configuration succeeded...

--> Do you want to run a cmake GUI to adjust the configuration? [y/N]
./configure: línea 64: ccmake: orden no encontrada (command not found)

========================= Configuration done ============================

   Ok, now just "cd build", "make" and "sudo make install"...

Maybe, is this related?

Created attachment 84466 [details]
Bespin debug

I think not, the problem related to the line 64 of the configure file is not related. I have corrected the command from ccmake to cmake, compiled and installed Bespin again, and the crash is still reproducible

There's a NULL object in the children list of apparently "kwebkitpart".

No idea what funky stuff happens to cause this, but that can of course be detected and skipped - i'll push a bespin update in a few minutes.

*Notice*, that this does not seem sane.
I'll bypass the known segfault, but guess that this should rather not happen - and may cause other segfaults, bespin or not.

-- OT --
"ccmake" is a curses ("text gui") frontend for cmake based reconfiguration
there's nothing "wrong", it's just not installed because ubuntu apparently separated it into a "cmake-curses-gui" package (while the script just assumes that if you got cmake, you "of course" also got ccmake)

-> r1709

Is it supposed that the crash is avoided with r1709?

Yes.
If not, you'll have to run the debug patch again.

Sorry, I can't apply the patch this time, I get this error:

$ patch --verbose < parche.patch
Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|Index: bespin.cpp
|===================================================================
|--- bespin.cpp (Revision 1707)
|+++ bespin.cpp (Arbeitskopie)
--------------------------
Patching file bespin.cpp using Plan A...
Hunk #1 FAILED at 1082.
1 out of 1 hunk FAILED -- saving rejects to file bespin.cpp.rej
done

I don't know how to solve this.

Created attachment 84468 [details]
Bespin debug 2

Updated debug patch.

So it still does crash in

detectBlurRegion(QWidget*, QWidget const*, QRegion&) () from /usr/lib/x86_64-linux-gnu/qt4/plugins/styles/libbespin.so

?

Sorry, I think I have fallen in a mistake. By using revision 1709 Konqueror does not crash. I can't reproduce the crash, now.

Thank you so much, you are very gentle.

Nevermind - I largely prefer that over a completely weird bug on top =)

@Devs
Any idea why kwebkitpart could have one (or two) NULL children?

The function is entered by a timer and called for a list of non NULL QWeakPointer<QWidget>::data() and recursively their children()

It *looks* as if i would jump into the destruction of kwebkitpart or a reparenting (with the child nulled, but not yet unlisted from children)

-> Does kpartwidget move widgets (toplevel windows) to other threads?
Or any other idea how this could happen?

Thomas, do I understand you correctly, that the bug is in KWebKit part? Please set the bug status accordingly.

I do not know where the issue is.

What is known so far is that when one changes konquerors backend from Webkit to KHTML, there will -eventually- be a NULL QObject child in a visible kwebkitpart widget, what should be impossible but for
a) a major bug in QtCore ...
b) threading, but iirc it should not be possible to have a (visible or not) QWidget in a non GUI thread and children cannot be in a different thread than their parent either
because removing is supposed to be atomic, deleting a child would remove it and that happens on a direct connection (so no chance for the timer to fire inbetween - where there also would be no NULL but a dangeling pointer)

Something *is* fishy here, but i have not enough insight to point  a culprit (could e.g. still be bespin as well)
Unfortunately i was neither able to reproduce this for investigation :-(

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!