Bug 232182

Summary: Crash when dragging a file/item over a taskbar entry of a window in another virtual desktop (virtual desktop changes while in the middle of the D&D operation) [null QGraphicsItemPrivate::q_func, QGraphicsItemPrivate::genericMapFromScene, QGraphicsScenePri
Product: [Unmaintained] plasma4 Reporter: Elias Probst <mail>
Component: generalAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED UPSTREAM    
Severity: crash CC: andresbajotierra, aseigo, bogdan.bivolaru, darktears31, nancy, t.ratovo
Priority: NOR    
Version: unspecified   
Target Milestone: ---   
Platform: Gentoo Packages   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Elias Probst 2010-03-26 07:35:47 UTC 
Application: plasma-desktop (0.3)
KDE Platform Version: 4.4.1 (KDE 4.4.1)
Qt Version: 4.6.2
Operating System: Linux 2.6.33 x86_64
Distribution (Platform): Gentoo Packages

-- Information about the crash:
1. Opened chromium on virtual desktop 1
2. Opened bangarang on virtual desktop 1
3. Moved bangarang to virtual desktop 2 by using the KWin present workspaces effect
4. Went back to virtual desktop 1
5. Dragged a stream playlist URL from chromium to bangarang's entry in the task manager (this entry was actually false to be there, as I have enabled the setting "Only show windows from current desktop")
6. Waited for a moment to auto switch to virtual desktop
7. Moved the mouse from the taskmanager area upon the desktop towards the bangarang window
8. plasma-desktop crashed

Couldn't reproduce this due to the fact, that I could reproduce the false behaviour of the task manager to show an entry from another desktop which actually shouldn't be there.

The crash does not seem to be reproducible.

 -- Backtrace:
Application: Plasma-Arbeitsfläche (kdeinit4), signal: Segmentation fault
Traceback (most recent call last):
  File "/usr/share/gdb/auto-load/usr/lib64/libgobject-2.0.so.0.2200.4-gdb.py", line 9, in <module>
    from gobject import register
  File "/usr/share/glib-2.0/gdb/gobject.py", line 3, in <module>
    import gdb.backtrace
ImportError: No module named backtrace
[Current thread is 1 (Thread 0x7f1578eea740 (LWP 13040))]

Thread 5 (Thread 0x7f1556f63910 (LWP 16323)):
#0  0x00007f15771cc199 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f1577457267 in QWaitConditionPrivate::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f156d553c3f in ThreadWeaver::WeaverImpl::blockThreadUntilJobsAreBeingAssigned(ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f156d555d90 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#8  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#9  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#10 0x00007f156d55474c in ThreadWeaver::ThreadRunHelper::run(ThreadWeaver::WeaverImpl*, ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#11 0x00007f156d554ab1 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#12 0x00007f1577456441 in QThreadPrivate::start (arg=0x1850020) at thread/qthread_unix.cpp:248
#13 0x00007f15771c82a7 in start_thread () from /lib/libpthread.so.0
#14 0x00007f1575fff6ad in clone () from /lib/libc.so.6
#15 0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7f1555ed4910 (LWP 16324)):
#0  0x00007f15771cc199 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f1577457267 in QWaitConditionPrivate::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f156d553c3f in ThreadWeaver::WeaverImpl::blockThreadUntilJobsAreBeingAssigned(ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f156d555d90 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f156d555da9 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f156d55474c in ThreadWeaver::ThreadRunHelper::run(ThreadWeaver::WeaverImpl*, ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#8  0x00007f156d554ab1 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#9  0x00007f1577456441 in QThreadPrivate::start (arg=0x1dc3940) at thread/qthread_unix.cpp:248
#10 0x00007f15771c82a7 in start_thread () from /lib/libpthread.so.0
#11 0x00007f1575fff6ad in clone () from /lib/libc.so.6
#12 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f154ffff910 (LWP 16325)):
#0  0x00007f15771cc199 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f1577457267 in QWaitConditionPrivate::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f156d553c3f in ThreadWeaver::WeaverImpl::blockThreadUntilJobsAreBeingAssigned(ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f156d555d90 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f156d55474c in ThreadWeaver::ThreadRunHelper::run(ThreadWeaver::WeaverImpl*, ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f156d554ab1 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f1577456441 in QThreadPrivate::start (arg=0x16680a0) at thread/qthread_unix.cpp:248
#8  0x00007f15771c82a7 in start_thread () from /lib/libpthread.so.0
#9  0x00007f1575fff6ad in clone () from /lib/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f154f7fe910 (LWP 16326)):
#0  0x00007f15771cc199 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f1577457267 in QWaitConditionPrivate::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x1887808, mutex=0x187ba40, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f156d553c3f in ThreadWeaver::WeaverImpl::blockThreadUntilJobsAreBeingAssigned(ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#4  0x00007f156d555d90 in ThreadWeaver::WorkingHardState::applyForWork(ThreadWeaver::Thread*, ThreadWeaver::Job*) () from /usr/lib64/libthreadweaver.so.4
#5  0x00007f156d55474c in ThreadWeaver::ThreadRunHelper::run(ThreadWeaver::WeaverImpl*, ThreadWeaver::Thread*) () from /usr/lib64/libthreadweaver.so.4
#6  0x00007f156d554ab1 in ThreadWeaver::Thread::run() () from /usr/lib64/libthreadweaver.so.4
#7  0x00007f1577456441 in QThreadPrivate::start (arg=0x177f9e0) at thread/qthread_unix.cpp:248
#8  0x00007f15771c82a7 in start_thread () from /lib/libpthread.so.0
#9  0x00007f1575fff6ad in clone () from /lib/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f1578eea740 (LWP 13040)):
[KCrash Handler]
#5  QGraphicsItemPrivate::q_func (this=0x0, pos=..., viewport=0x1a5aad0) at graphicsview/qgraphicsitem_p.h:103
#6  QGraphicsItemPrivate::genericMapFromScene (this=0x0, pos=..., viewport=0x1a5aad0) at graphicsview/qgraphicsitem.cpp:915
#7  0x00007f1576ced1bc in QGraphicsScenePrivate::sendDragDropEvent (this=0x6f5690, item=0x29791e0, dragDropEvent=0x7fff3d054e40) at graphicsview/qgraphicsscene.cpp:1209
#8  0x00007f1576cf555e in QGraphicsScene::dragMoveEvent (this=<value optimized out>, event=0x7fff3d055630) at graphicsview/qgraphicsscene.cpp:3631
#9  0x00007f1576d01c59 in QGraphicsScene::event (this=0x6d2410, event=0x7fff3d055630) at graphicsview/qgraphicsscene.cpp:3343
#10 0x00007f157674c8a6 in QApplicationPrivate::notify_helper (this=0x696f70, receiver=0x6d2410, e=0x7fff3d055630) at kernel/qapplication.cpp:4300
#11 0x00007f1576753354 in QApplication::notify (this=0x681260, receiver=0x6d2410, e=0x7fff3d055630) at kernel/qapplication.cpp:3704
#12 0x00007f1577a6a764 in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#13 0x00007f1577536334 in QCoreApplication::notifyInternal (this=0x681260, receiver=0x6d2410, event=0x7fff3d055630) at kernel/qcoreapplication.cpp:704
#14 0x00007f1576d1a0d5 in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fff3d056000) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#15 QGraphicsView::dragMoveEvent (this=<value optimized out>, event=0x7fff3d056000) at graphicsview/qgraphicsview.cpp:2939
#16 0x00007f157679a298 in QWidget::event (this=0x14d2db0, event=0x7fff3d056000) at kernel/qwidget.cpp:8196
#17 0x00007f1576b0bc66 in QFrame::event (this=0x14d2db0, e=0x7fff3d056000) at widgets/qframe.cpp:557
#18 0x00007f1576d17da9 in QGraphicsView::viewportEvent (this=0x14d2db0, event=0x7fff3d056000) at graphicsview/qgraphicsview.cpp:2787
#19 0x00007f157753597a in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value optimized out>, receiver=0x1a5aad0, event=0x7fff3d056000) at kernel/qcoreapplication.cpp:819
#20 0x00007f157674c885 in QApplicationPrivate::notify_helper (this=0x696f70, receiver=0x1a5aad0, e=0x7fff3d056000) at kernel/qapplication.cpp:4296
#21 0x00007f1576753cfa in QApplication::notify (this=<value optimized out>, receiver=0x1a5aad0, e=0x7fff3d056000) at kernel/qapplication.cpp:4108
#22 0x00007f1577a6a764 in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#23 0x00007f1577536334 in QCoreApplication::notifyInternal (this=0x681260, receiver=0x1a5aad0, event=0x7fff3d056000) at kernel/qcoreapplication.cpp:704
#24 0x00007f15767d4561 in handle_xdnd_position (w=0x14d2db0, xe=0x7fff3d056860, passive=false) at kernel/qdnd_x11.cpp:928
#25 0x00007f15767b7818 in QApplication::x11ClientMessage (this=<value optimized out>, w=0x14d2db0, event=0x7fff3d056860, passive_only=96) at kernel/qapplication_x11.cpp:3080
#26 0x00007f15767c7724 in QApplication::x11ProcessEvent (this=0x681260, event=0x7fff3d056860) at kernel/qapplication_x11.cpp:3633
#27 0x00007f15767ee04a in x11EventSourceDispatch (s=0x69a5d0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#28 0x00007f1572a150d3 in g_main_dispatch (context=0x699520) at gmain.c:1960
#29 IA__g_main_context_dispatch (context=0x699520) at gmain.c:2513
#30 0x00007f1572a181cc in g_main_context_iterate (context=0x699520, block=1, dispatch=1, self=<value optimized out>) at gmain.c:2591
#31 0x00007f1572a1834e in IA__g_main_context_iteration (context=0x699520, may_block=1) at gmain.c:2654
#32 0x00007f157755bcb4 in QEventDispatcherGlib::processEvents (this=0x616930, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:412
#33 0x00007f15767edc66 in QGuiEventDispatcherGlib::processEvents (this=0x0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#34 0x00007f1577534ff4 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#35 0x00007f157753533f in QEventLoop::exec (this=0x7fff3d056b90, flags=...) at kernel/qeventloop.cpp:201
#36 0x00007f157753731e in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#37 0x00007f156b58ed81 in kdemain () from /usr/lib64/libkdeinit4_plasma-desktop.so
#38 0x0000000000407145 in launch(int, char const*, char const*, char const*, int, char const*, bool, char const*, bool, char const*) ()
#39 0x00000000004076f2 in handle_launcher_request(int, char const*) ()
#40 0x0000000000407cd7 in handle_requests(int) ()
#41 0x0000000000408907 in main ()

Reported using DrKonqi
Comment 1 Elias Probst 2010-03-26 10:57:12 UTC 
I found a way to reproduce this crash:
- Make sure the task manager is configured to show only windows from the current desktop
- Make sure the window of bangarang is on another virtual desktop than the current one
- Click the bangarang icon once
- Bangarang appears in the task manager although it still resides on another desktop
- Drag something onto the task manager entry of bangarang
- KWin switches to the virtual desktop where bangarang resides
- While dragging the item now away from the taskbar towards the bangarang window, plasma-desktop crashes.
Comment 2 Dario Andres 2010-03-26 13:19:20 UTC 
I could reproduce the crash using the provided steps. 
Here using:

Qt: 4.6.2 (kde-qt master commit 62cda737405d0f2163094c44189cfd71ca3c576a
        Date:   Mon Feb 15 14:37:02 2010 +0100)
KDE Development Platform: 4.4.69 (KDE 4.4.69 (KDE 4.5 >= 20100324))
kdelibs svn rev. 1107102 / kdebase svn rev. 1107102
on ArchLinux i686 - Kernel 2.6.32.10

I just used a Konqueror window on another virtual desktop, dragging a .desktop file from my FolderView widget...

Backtrace:
---

Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0xb2d13720 (LWP 6105))]

Thread 2 (Thread 0xa730db70 (LWP 6111)):
#0  0xb77bb424 in __kernel_vsyscall ()
#1  0xb52cee55 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb757f489 in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0xb76bda20) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2304
#3  0xb757ebdb in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=0xb76bda20) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1438
#4  0xb52ca8ac in start_thread () from /lib/libpthread.so.0
#5  0xb511401e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb2d13720 (LWP 6105)):
[KCrash Handler]
#7  0xb5f28744 in QGraphicsItemPrivate::q_func (this=0x20) at graphicsview/qgraphicsitem_p.h:103
#8  0xb5f0a738 in QGraphicsItemPrivate::genericMapFromScene (this=0x20, pos=..., viewport=0x8c14748) at graphicsview/qgraphicsitem.cpp:915
#9  0xb5f43be9 in QGraphicsScenePrivate::sendDragDropEvent (this=0x881ce10, item=0x9365768, dragDropEvent=0xbfc17c44) at graphicsview/qgraphicsscene.cpp:1209
#10 0xb5f4b09e in QGraphicsScene::dragMoveEvent (this=0x88012d8, event=0xbfc182cc) at graphicsview/qgraphicsscene.cpp:3631
#11 0xb7185ca6 in Plasma::Corona::dragMoveEvent (this=0x88012d8, event=0xbfc182cc) at /home/kde-devel/kde/src/KDE/kdelibs/plasma/corona.cpp:785
#12 0xb5f4a0ae in QGraphicsScene::event (this=0x88012d8, event=0xbfc182cc) at graphicsview/qgraphicsscene.cpp:3343
#13 0xb57e6cd6 in QApplicationPrivate::notify_helper (this=0x8738038, receiver=0x88012d8, e=0xbfc182cc) at kernel/qapplication.cpp:4300
#14 0xb57e4418 in QApplication::notify (this=0x872fa38, receiver=0x88012d8, e=0xbfc182cc) at kernel/qapplication.cpp:3704
#15 0xb69362b8 in KApplication::notify (this=0x872fa38, receiver=0x88012d8, event=0xbfc182cc) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:302
#16 0xb5471935 in QCoreApplication::notifyInternal (this=0x872fa38, receiver=0x88012d8, event=0xbfc182cc) at kernel/qcoreapplication.cpp:704
#17 0xb57d729d in QCoreApplication::sendEvent (receiver=0x88012d8, event=0xbfc182cc) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#18 0xb5f78dcc in QGraphicsView::dragMoveEvent (this=0x8c14d58, event=0xbfc18b44) at graphicsview/qgraphicsview.cpp:2939
#19 0xb5852dab in QWidget::event (this=0x8c14d58, event=0xbfc18b44) at kernel/qwidget.cpp:8196
#20 0xb5cd4934 in QFrame::event (this=0x8c14d58, e=0xbfc18b44) at widgets/qframe.cpp:557
#21 0xb5d8239d in QAbstractScrollArea::viewportEvent (this=0x8c14d58, e=0xbfc18b44) at widgets/qabstractscrollarea.cpp:1036
#22 0xb5f78563 in QGraphicsView::viewportEvent (this=0x8c14d58, event=0xbfc18b44) at graphicsview/qgraphicsview.cpp:2787
#23 0xb5d82f01 in QAbstractScrollAreaPrivate::viewportEvent (this=0x8d2f288, event=0xbfc18b44) at widgets/qabstractscrollarea_p.h:100
#24 0xb5d82fe8 in QAbstractScrollAreaFilter::eventFilter (this=0x8c82948, o=0x8c14748, e=0xbfc18b44) at widgets/qabstractscrollarea_p.h:116
#25 0xb5471c13 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x8738038, receiver=0x8c14748, event=0xbfc18b44) at kernel/qcoreapplication.cpp:819
#26 0xb57e6cb2 in QApplicationPrivate::notify_helper (this=0x8738038, receiver=0x8c14748, e=0xbfc18b44) at kernel/qapplication.cpp:4296
#27 0xb57e5ed8 in QApplication::notify (this=0x872fa38, receiver=0x8c14748, e=0xbfc18b44) at kernel/qapplication.cpp:4108
#28 0xb69362b8 in KApplication::notify (this=0x872fa38, receiver=0x8c14748, event=0xbfc18b44) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:302
#29 0xb5471935 in QCoreApplication::notifyInternal (this=0x872fa38, receiver=0x8c14748, event=0xbfc18b44) at kernel/qcoreapplication.cpp:704
#30 0xb57d729d in QCoreApplication::sendEvent (receiver=0x8c14748, event=0xbfc18b44) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#31 0xb589b7ce in handle_xdnd_position (w=0x8c14d58, xe=0xbfc18cf0, passive=false) at kernel/qdnd_x11.cpp:928
#32 0xb589dd47 in QDragManager::move (this=0x950fc40, globalPos=...) at kernel/qdnd_x11.cpp:1643
#33 0xb589c92e in QDragManager::eventFilter (this=0x950fc40, o=0x8b91018, e=0xbfc194cc) at kernel/qdnd_x11.cpp:1287
#34 0xb5471b2a in QCoreApplicationPrivate::sendThroughApplicationEventFilters (this=0x8738038, receiver=0x8b91018, event=0xbfc194cc) at kernel/qcoreapplication.cpp:800
#35 0xb57e6b92 in QApplicationPrivate::notify_helper (this=0x8738038, receiver=0x8b91018, e=0xbfc194cc) at kernel/qapplication.cpp:4275
#36 0xb57e4d55 in QApplication::notify (this=0x872fa38, receiver=0x8b91018, e=0xbfc194cc) at kernel/qapplication.cpp:3865
#37 0xb69362b8 in KApplication::notify (this=0x872fa38, receiver=0x8b91018, event=0xbfc194cc) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:302
#38 0xb5471935 in QCoreApplication::notifyInternal (this=0x872fa38, receiver=0x8b91018, event=0xbfc194cc) at kernel/qcoreapplication.cpp:704
#39 0xb57e9a8d in QCoreApplication::sendSpontaneousEvent (receiver=0x8b91018, event=0xbfc194cc) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#40 0xb57e336f in QApplicationPrivate::sendMouseEvent (receiver=0x8b91018, event=0xbfc194cc, alienWidget=0x0, nativeWidget=0x8b91018, buttonDown=0xb62d9638, lastMouseReceiver=..., spontaneous=true)
    at kernel/qapplication.cpp:2963
#41 0xb5889052 in QETWidget::translateMouseEvent (this=0x8b91018, event=0xbfc199f0) at kernel/qapplication_x11.cpp:4368
#42 0xb5885c92 in QApplication::x11ProcessEvent (this=0x872fa38, event=0xbfc199f0) at kernel/qapplication_x11.cpp:3379
#43 0xb58bc291 in x11EventSourceDispatch (s=0x873aef0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#44 0xb344f398 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#45 0xb3452c10 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#46 0xb3452d43 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#47 0xb54a9338 in QEventDispatcherGlib::processEvents (this=0x8700e50, flags=...) at kernel/qeventdispatcher_glib.cpp:412
#48 0xb58bc8c6 in QGuiEventDispatcherGlib::processEvents (this=0x8700e50, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#49 0xb546ed0f in QEventLoop::processEvents (this=0x8dcbd80, flags=...) at kernel/qeventloop.cpp:149
#50 0xb546ee54 in QEventLoop::exec (this=0x8dcbd80, flags=...) at kernel/qeventloop.cpp:201
#51 0xb589efbc in QDragManager::drag (this=0x950fc40, o=0x9362300) at kernel/qdnd_x11.cpp:1960
#52 0xb57fa9e8 in QDrag::exec (this=0x9362300, supportedActions=..., defaultDropAction=Qt::IgnoreAction) at kernel/qdrag.cpp:282
#53 0xb57fa88c in QDrag::exec (this=0x9362300, supportedActions=...) at kernel/qdrag.cpp:239
#54 0xa76af9f4 in IconView::startDrag (this=0x8d0a410, pos=..., widget=0x8a38a10) at /home/kde-devel/kde/src/KDE/kdebase/apps/plasma/applets/folderview/iconview.cpp:2427
#55 0xa76ac8ff in IconView::mouseMoveEvent (this=0x8d0a410, event=0xbfc1a9c8) at /home/kde-devel/kde/src/KDE/kdebase/apps/plasma/applets/folderview/iconview.cpp:1942
#56 0xb5f1acfa in QGraphicsItem::sceneEvent (this=0x8d0a418, event=0xbfc1a9c8) at graphicsview/qgraphicsitem.cpp:6493
#57 0xb5f8114d in QGraphicsWidget::sceneEvent (this=0x8d0a410, event=0xbfc1a9c8) at graphicsview/qgraphicswidget.cpp:1129
#58 0xb5f43a02 in QGraphicsScenePrivate::sendEvent (this=0x881ce10, item=0x8d0a418, event=0xbfc1a9c8) at graphicsview/qgraphicsscene.cpp:1181
#59 0xb5f44166 in QGraphicsScenePrivate::sendMouseEvent (this=0x881ce10, mouseEvent=0xbfc1a9c8) at graphicsview/qgraphicsscene.cpp:1255
#60 0xb5f4c1c6 in QGraphicsScene::mouseMoveEvent (this=0x88012d8, mouseEvent=0xbfc1a9c8) at graphicsview/qgraphicsscene.cpp:4031
#61 0xb5f4a3cf in QGraphicsScene::event (this=0x88012d8, event=0xbfc1a9c8) at graphicsview/qgraphicsscene.cpp:3391
#62 0xb57e6cd6 in QApplicationPrivate::notify_helper (this=0x8738038, receiver=0x88012d8, e=0xbfc1a9c8) at kernel/qapplication.cpp:4300
#63 0xb57e4418 in QApplication::notify (this=0x872fa38, receiver=0x88012d8, e=0xbfc1a9c8) at kernel/qapplication.cpp:3704
#64 0xb69362b8 in KApplication::notify (this=0x872fa38, receiver=0x88012d8, event=0xbfc1a9c8) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:302
#65 0xb5471935 in QCoreApplication::notifyInternal (this=0x872fa38, receiver=0x88012d8, event=0xbfc1a9c8) at kernel/qcoreapplication.cpp:704
#66 0xb57e9a8d in QCoreApplication::sendSpontaneousEvent (receiver=0x88012d8, event=0xbfc1a9c8) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#67 0xb57e702f in qt_sendSpontaneousEvent (receiver=0x88012d8, event=0xbfc1a9c8) at kernel/qapplication.cpp:5279
#68 0xb5f7082b in QGraphicsViewPrivate::mouseMoveEventHandler (this=0x8a25690, event=0xbfc1b47c) at graphicsview/qgraphicsview.cpp:645
#69 0xb5f79fa8 in QGraphicsView::mouseMoveEvent (this=0x8a419d8, event=0xbfc1b47c) at graphicsview/qgraphicsview.cpp:3197
#70 0xb58523f6 in QWidget::event (this=0x8a419d8, event=0xbfc1b47c) at kernel/qwidget.cpp:7983
#71 0xb5cd4934 in QFrame::event (this=0x8a419d8, e=0xbfc1b47c) at widgets/qframe.cpp:557
#72 0xb5d8239d in QAbstractScrollArea::viewportEvent (this=0x8a419d8, e=0xbfc1b47c) at widgets/qabstractscrollarea.cpp:1036
#73 0xb5f78563 in QGraphicsView::viewportEvent (this=0x8a419d8, event=0xbfc1b47c) at graphicsview/qgraphicsview.cpp:2787
#74 0xb5d82f01 in QAbstractScrollAreaPrivate::viewportEvent (this=0x8a25690, event=0xbfc1b47c) at widgets/qabstractscrollarea_p.h:100
#75 0xb5d82fe8 in QAbstractScrollAreaFilter::eventFilter (this=0x8a36bd0, o=0x8a38a10, e=0xbfc1b47c) at widgets/qabstractscrollarea_p.h:116
#76 0xb5471c13 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x8738038, receiver=0x8a38a10, event=0xbfc1b47c) at kernel/qcoreapplication.cpp:819
#77 0xb57e6cb2 in QApplicationPrivate::notify_helper (this=0x8738038, receiver=0x8a38a10, e=0xbfc1b47c) at kernel/qapplication.cpp:4296
#78 0xb57e4d55 in QApplication::notify (this=0x872fa38, receiver=0x8a38a10, e=0xbfc1b47c) at kernel/qapplication.cpp:3865
#79 0xb69362b8 in KApplication::notify (this=0x872fa38, receiver=0x8a38a10, event=0xbfc1b47c) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:302
#80 0xb5471935 in QCoreApplication::notifyInternal (this=0x872fa38, receiver=0x8a38a10, event=0xbfc1b47c) at kernel/qcoreapplication.cpp:704
#81 0xb57e9a8d in QCoreApplication::sendSpontaneousEvent (receiver=0x8a38a10, event=0xbfc1b47c) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#82 0xb57e336f in QApplicationPrivate::sendMouseEvent (receiver=0x8a38a10, event=0xbfc1b47c, alienWidget=0x8a38a10, nativeWidget=0x8a419d8, buttonDown=0xb62d9638, lastMouseReceiver=..., 
    spontaneous=true) at kernel/qapplication.cpp:2963
#83 0xb5889052 in QETWidget::translateMouseEvent (this=0x8a419d8, event=0xbfc1b9a0) at kernel/qapplication_x11.cpp:4368
#84 0xb5885c92 in QApplication::x11ProcessEvent (this=0x872fa38, event=0xbfc1b9a0) at kernel/qapplication_x11.cpp:3379
#85 0xb58bc291 in x11EventSourceDispatch (s=0x873aef0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#86 0xb344f398 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#87 0xb3452c10 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#88 0xb3452d43 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#89 0xb54a9338 in QEventDispatcherGlib::processEvents (this=0x8700e50, flags=...) at kernel/qeventdispatcher_glib.cpp:412
#90 0xb58bc8c6 in QGuiEventDispatcherGlib::processEvents (this=0x8700e50, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#91 0xb546ed0f in QEventLoop::processEvents (this=0xbfc1bc7c, flags=...) at kernel/qeventloop.cpp:149
#92 0xb546ee54 in QEventLoop::exec (this=0xbfc1bc7c, flags=...) at kernel/qeventloop.cpp:201
#93 0xb5472011 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#94 0xb57e4026 in QApplication::exec () at kernel/qapplication.cpp:3579
#95 0xb7784d41 in kdemain (argc=3, argv=0xbfc1be94) at /home/kde-devel/kde/src/KDE/kdebase/workspace/plasma/desktop/shell/main.cpp:118
#96 0x080487c9 in main (argc=3, argv=0xbfc1be94) at /home/kde-devel/kde/build/KDE/kdebase/workspace/plasma/desktop/shell/plasma-desktop_dummy.cpp:3
Comment 3 Dario Andres 2010-03-26 13:21:51 UTC 
*** Bug 227050 has been marked as a duplicate of this bug. ***
Comment 4 Dario Andres 2010-03-26 13:22:27 UTC 
Bug 210941 looks like an old version/case of this crash
Comment 5 Aaron J. Seigo 2010-05-08 23:41:46 UTC 
this is a crash in qt; it's not checking the value of item->d_ptr in  QGraphicsScenePrivate::sendDragDropEvent and/or is not clearing the event target when the item is deleted.
Comment 6 Elias Probst 2010-05-09 21:29:22 UTC 
(In reply to comment #5)
> this is a crash in qt; it's not checking the value of item->d_ptr in 
> QGraphicsScenePrivate::sendDragDropEvent and/or is not clearing the event
> target when the item is deleted.

Is there a corresponding upstream bug report yet? It would be probably helpful to link it here.
Comment 7 Alexis MENARD 2010-05-10 06:17:49 UTC 
I can't reproduce the crash with 4.4.3 either with Qt 4.6 and Qt 4.7

I tried the bangarang steps :

"I found a way to reproduce this crash:
- Make sure the task manager is configured to show only windows from the
current desktop -> done
- Make sure the window of bangarang is on another virtual desktop than the
current one -> done
- Click the bangarang icon once -> which one where? systray/taskbar??
- Bangarang appears in the task manager although it still resides on another
desktop -> well I don't see that"

That fails for me. Bangarang is let say on desktop 2, I'm on desktop one and I don't see any task entry of bangarang.

I tried the dario andres steps but same how you can drop stuff on the Konqueror taks if it's in another desktop and you have the option "show only tasks from the current desktop". For me the former option works fine.

I also tried without the "show only tasks from the current desktop" and i was not able to reproduce.
Comment 8 Alexis MENARD 2010-05-12 07:20:01 UTC 
Ok resolved for 4.7.0 sha key 798bdb4543f84d427659b950a3a1643ae4987b8b
Comment 9 Aaron J. Seigo 2010-05-13 01:17:32 UTC 
great, Alexis, thanks! :)
Comment 10 Dario Andres 2010-12-29 13:47:36 UTC 
*** Bug 261531 has been marked as a duplicate of this bug. ***
Comment 11 Nancy Anthracite 2010-12-29 13:54:19 UTC 
I did an aptitude reinstall of Iceweasel after it would not open and my automated bug report was marked as a duplicate of this one.  Iceweasel now opens.  I am not sure if it could be related, but I have been trying to install the very latest flash player plugin recently as a web site I want to use requires it.  I don't know if that could relate to this.
Comment 12 Dario Andres 2011-08-07 12:59:18 UTC 
*** Bug 279574 has been marked as a duplicate of this bug. ***