What QT version and KDEsvn revision are you using ?

I'm using qt 4.4.3 provided by neon(nightly) packages in ubuntu.  I am on svn896517.  If this sounds completely bogus I am sorry and if packaging is the cause I will quit reporting any bugs from these nightly packages.

It seems to be a QT bug (may be related to some nightly/unstable patch). Can you install a stable QT4.4.3 ? (I don't know if exists on stable ubuntu repos or something). If you can install it, can you reproduce the bug again ? Thanks :)

*** Bug 177772 has been marked as a duplicate of this bug. ***

I quote Dario, seems more a bug in Qt, I have just rebuilt the whole KDE and I can't reproduce this.

The qt-copy that we neon users have been using got out of date and does not have some of the patches, but it will be updated soon I am told.  Looks like the last update was 10-24-2008.

Mh, I experienced this bug some minutes ago :(
Here using:

Qt: 4.4.3 + qt-copy-patches-889120
KDE: 4.1.85 (KDE 4.1.85 (KDE 4.2 Beta2))
kdelibs svn rev. 899634 / kdebase svn rev. 899635
on ArchLinux x86_64 - Kernel 2.6.27.8

Backtrace:

ASSERT: "uniformSpacer >= 0 || spacing >= 0" in file ../../include/QtGui/private/../../../src/gui/kernel/qlayoutengine_p.h, line 74

Application: System Settings (systemsettings), signal SIGABRT
0x00007f6b074abfd0 in __nanosleep_nocancel () from /lib/libc.so.6

Thread 1 (Thread 0x7f6b0ac2d750 (LWP 16846)):
[KCrash Handler]
#5  0x00007f6b0743f0c5 in raise () from /lib/libc.so.6
#6  0x00007f6b074405e3 in abort () from /lib/libc.so.6
#7  0x00007f6b08e4aa25 in qt_message_output (msgType=QtFatalMsg, buf=<value optimized out>) at global/qglobal.cpp:2102
#8  0x00007f6b08e4ab47 in qFatal (msg=<value optimized out>) at global/qglobal.cpp:2303
#9  0x00007f6b080cbc98 in qGeomCalc (chain=@0x22f85b0, start=0, count=<value optimized out>, pos=4, space=284, spacer=-1) at ../../include/QtGui/private/../../../src/gui/kernel/qlayoutengine_p.h:74
#10 0x00007f6b080bcdef in QFormLayout::setGeometry (this=0x22f8470, rect=@0x7fff12d67050) at kernel/qformlayout.cpp:1488
#11 0x00007f6b080c9557 in QLayoutPrivate::doResize (this=0x22f84a0, r=@0x7fff12d670d0) at kernel/qlayout.cpp:630
#12 0x00007f6b080c96ac in QLayout::activate (this=0x22f8470) at kernel/qlayout.cpp:1203
#13 0x00007f6b080f1853 in QWidget::setVisible (this=0x22f7b30, visible=<value optimized out>) at kernel/qwidget.cpp:6551
#14 0x00007f6b0845d5c8 in QScrollArea::setWidget (this=0x23285c0, widget=0x22f7b30) at ../../include/QtGui/../../src/gui/kernel/qwidget.h:464
#15 0x00007f6b084532a9 in QToolBox::insertItem (this=0x2310a70, index=-1, widget=0x22f7b30, icon=@0x7fff12d67320, text=@0x7fff12d67390) at widgets/qtoolbox.cpp:371
#16 0x00007f6affdace83 in Ui_profileEditPage::setupUi (this=0x230cdc8, profileEditPage=0x230cda0) at /usr/include/QtGui/qtoolbox.h:131
#17 0x00007f6affda8c6c in EditPage (this=0x230cda0, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/EditPage.cpp:52
#18 0x00007f6affd9c4f9 in ConfigWidget (this=0x22a8d60, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/ConfigWidget.cpp:28
#19 0x00007f6affd9a5e6 in PowerDevilKCM::initView (this=0x2277a90) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:111
#20 0x00007f6affd9b118 in PowerDevilKCM::initModule (this=0x2277a90) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:98
#21 0x00007f6affd9b785 in PowerDevilKCM (this=0x2277a90, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:74
#22 0x00007f6affd9c203 in KPluginFactory::createInstance<PowerDevilKCM, QWidget> (parentWidget=<value optimized out>, parent=<value optimized out>, args=@0x7fff12d68440)
    at /home/kde-devel/kde/include/KDE/../kpluginfactory.h:461
#23 0x00007f6b09655aed in KPluginFactory::create (this=0x224f940, iface=0x7f6b09c777a0 "KCModule", parentWidget=0x0, parent=0x224afb0, args=@0x7fff12d68440, keyword=@0x7fff12d68160)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/util/kpluginfactory.cpp:191
#24 0x00007f6b0a91c5b6 in KService::createInstance<KCModule> (service=<value optimized out>, parent=0x224afb0, args=@0x7fff12d68440, error=0x7fff12d68450)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/util/kpluginfactory.h:515
#25 0x00007f6b0a91b604 in KCModuleLoader::loadModule (mod=@0x224def0, report=KCModuleLoader::Inline, parent=0x224afb0, args=@0x224dec0)
    at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleloader.cpp:90
#26 0x00007f6b0a92123a in KCModuleProxyPrivate::loadModule (this=0x224dec0) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:107
#27 0x00007f6b0a922225 in KCModuleProxy::realModule (this=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:83
#28 0x00007f6b0a92234c in KCModuleProxy::buttons (this=0x41ce) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:300
#29 0x000000000040ebab in KCMultiWidget::slotAboutToShow (this=0x1fc44b0, page=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/systemsettings/kcmultiwidget.cpp:264
#30 0x0000000000410558 in KCMultiWidget::addModule (this=0x1fc44b0, moduleinfo=@0x1ce1990) at /home/kde-devel/kde/src/KDE/kdebase/workspace/systemsettings/kcmultiwidget.cpp:208
#31 0x0000000000414ec0 in MainWindow::selectionChanged (this=0x1bcca70, selected=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/systemsettings/mainwindow.cpp:330
#32 0x000000000041501d in MainWindow::qt_metacall (this=0x1bcca70, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0x7fff12d68f20)
    at /home/kde-devel/kde/build/KDE/kdebase/workspace/systemsettings/mainwindow.moc:70
#33 0x00007f6b08f45ac0 in QMetaObject::activate (sender=0x1fc1800, from_signal_index=<value optimized out>, to_signal_index=32, argv=0xffffffffffffffff) at kernel/qobject.cpp:3028
#34 0x00007f6b084dbcc5 in QAbstractItemView::clicked (this=0x41ce, _t1=<value optimized out>) at .moc/debug-shared/moc_qabstractitemview.cpp:316
#35 0x00007f6b084e87ce in QAbstractItemView::mouseReleaseEvent (this=0x1fc1800, event=0x7fff12d69ec0) at itemviews/qabstractitemview.cpp:1612
#36 0x00007f6b084fb967 in QListView::mouseReleaseEvent (this=0x41ce, e=0x41ce) at itemviews/qlistview.cpp:819
#37 0x00007f6b09af3d48 in KCategorizedView::mouseReleaseEvent (this=0x41ce, event=0x41ce) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/itemviews/kcategorizedview.cpp:1135
#38 0x00007f6b080f0cb4 in QWidget::event (this=0x1fc1800, event=0x7fff12d69ec0) at kernel/qwidget.cpp:7163
#39 0x00007f6b084e908d in QAbstractItemView::viewportEvent (this=0x1fc1800, event=0x7fff12d69ec0) at itemviews/qabstractitemview.cpp:1429
#40 0x00007f6b08f307f7 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value optimized out>, receiver=0x1fc1ee0, event=0x7fff12d69ec0) at kernel/qcoreapplication.cpp:694
#41 0x00007f6b0809e07c in QApplicationPrivate::notify_helper (this=0x1b59330, receiver=0x1fc1ee0, e=0x7fff12d69ec0) at kernel/qapplication.cpp:3799
#42 0x00007f6b080a5c65 in QApplication::notify (this=<value optimized out>, receiver=0x1fc1ee0, e=0x7fff12d69ec0) at kernel/qapplication.cpp:3528
#43 0x00007f6b09b0722b in KApplication::notify (this=0x7fff12d6ac50, receiver=0x1fc1ee0, event=0x7fff12d69ec0) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:307
#44 0x00007f6b08f30d90 in QCoreApplication::notifyInternal (this=0x7fff12d6ac50, receiver=0x1fc1ee0, event=0x7fff12d69ec0) at kernel/qcoreapplication.cpp:583
#45 0x00007f6b080a4fe2 in QApplicationPrivate::sendMouseEvent (receiver=0x1fc1ee0, event=0x7fff12d69ec0, alienWidget=0x0, nativeWidget=0x1fc1ee0, buttonDown=<value optimized out>, 
    lastMouseReceiver=@0x7f6b0898e450) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:212
#46 0x00007f6b08102bec in QETWidget::translateMouseEvent (this=0x1fc1ee0, event=<value optimized out>) at kernel/qapplication_x11.cpp:4044
#47 0x00007f6b08101d47 in QApplication::x11ProcessEvent (this=0x7c, event=0x7fff12d6a790) at kernel/qapplication_x11.cpp:3162
#48 0x00007f6b08126724 in x11EventSourceDispatch (s=0x1b534a0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:142
#49 0x00007f6b04699aa2 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#50 0x00007f6b0469d21d in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#51 0x00007f6b0469d3db in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#52 0x00007f6b08f57cdf in QEventDispatcherGlib::processEvents (this=0x1b19e60, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:319
#53 0x00007f6b08125f7f in QGuiEventDispatcherGlib::processEvents (this=0x41ce, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:198
#54 0x00007f6b08f2f9c2 in QEventLoop::processEvents (this=<value optimized out>, flags={i = 316058240}) at kernel/qeventloop.cpp:143
#55 0x00007f6b08f2fb55 in QEventLoop::exec (this=0x7fff12d6aac0, flags={i = 316058320}) at kernel/qeventloop.cpp:190
#56 0x00007f6b08f348f7 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:845
#57 0x00000000004116d7 in main (argc=1, argv=0x7fff12d6af78) at /home/kde-devel/kde/src/KDE/kdebase/workspace/systemsettings/main.cpp:67

Can anyone else confirm this with today's trunk ? (20081221)

*** Bug 178475 has been marked as a duplicate of this bug. ***

One more confirmed case in devel brach. Confirming

*** Bug 178520 has been marked as a duplicate of this bug. ***

The crash happens inside Qt, so I'm pretty sure it's a problem with Qt. Have you guys applied some patches to it, or using a different version from the one powerdevil has been compiled against?

Hi Dario.

Here I'm using both Qt 4.4.3 + qt-copy-patches-889120 (my distro (Arch)
default) for both compiling and running KDE4.2svn. (maybe some qt-copy patch
creates the bug ?)

I also tried installing Qt4.5beta and it crashed too (however I didn't
recompile all KDE with the 4.5beta, so It may be as expected to run into bugs)

Hi back Dario :)

Please try to recompile PowerDevil against standard Qt and/or Qt4.5 and see if the bug still persists.

Here after installing QT-4.5-snapshot-20081223 (I have it already compiled) and recompiling again the following stuff:

workspace/powerdevil/kcmodule
workspace/powerdevil/daemon
workspace/libs/solid/control

PowerDevil KCM keeps crashing :(

Backtrace:

Application: KDE Control Module (kcmshell4), signal SIGABRT
0x00007f6ba98eafd0 in __nanosleep_nocancel () from /lib/libc.so.6

Thread 1 (Thread 0x7f6bac975750 (LWP 20760)):
[KCrash Handler]
#5  0x00007f6ba987e0c5 in raise () from /lib/libc.so.6
#6  0x00007f6ba987f5e3 in abort () from /lib/libc.so.6
#7  0x00007f6bab36e755 in qt_message_output (msgType=QtFatalMsg, buf=<value optimized out>) at global/qglobal.cpp:1993
#8  0x00007f6bab36e870 in qFatal (msg=<value optimized out>) at global/qglobal.cpp:2188
#9  0x00007f6baa51a508 in qGeomCalc (chain=@0x1d2a110, start=0, count=<value optimized out>, pos=4, space=284, spacer=-1) at ../../include/QtGui/private/../../../src/gui/kernel/qlayoutengine_p.h:73
#10 0x00007f6baa50b66f in QFormLayout::setGeometry (this=0x1d29fd0, rect=@0x7fffb4ab35b0) at kernel/qformlayout.cpp:1487
#11 0x00007f6baa517dc7 in QLayoutPrivate::doResize (this=0x1d2a000, r=@0x7fffb4ab3630) at kernel/qlayout.cpp:632
#12 0x00007f6baa517f1c in QLayout::activate (this=0x1d29fd0) at kernel/qlayout.cpp:1205
#13 0x00007f6baa5404a3 in QWidget::setVisible (this=0x1d29700, visible=<value optimized out>) at kernel/qwidget.cpp:6796
#14 0x00007f6baa93e288 in QScrollArea::setWidget (this=0x1d34b30, widget=0x1d29700) at ../../include/QtGui/../../src/gui/kernel/qwidget.h:468
#15 0x00007f6baa933dbf in QToolBox::insertItem (this=0x1cb3130, index=-1, widget=0x1d29700, icon=@0x7fffb4ab3880, text=@0x7fffb4ab38c0) at widgets/qtoolbox.cpp:370
#16 0x00007f6ba13ec40b in Ui_profileEditPage::setupUi (this=0x1d1ced8, profileEditPage=0x1d1ceb0) at /usr/include/QtGui/qtoolbox.h:130
#17 0x00007f6ba13e819c in EditPage (this=0x1d1ceb0, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/EditPage.cpp:52
#18 0x00007f6ba13db599 in ConfigWidget (this=0x1c741c0, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/ConfigWidget.cpp:28
#19 0x00007f6ba13d9646 in PowerDevilKCM::initView (this=0x1c6c570) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:111
#20 0x00007f6ba13da1b8 in PowerDevilKCM::initModule (this=0x1c6c570) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:98
#21 0x00007f6ba13da825 in PowerDevilKCM (this=0x1c6c570, parent=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdebase/workspace/powerdevil/kcmodule/PowerDevilKCM.cpp:74
#22 0x00007f6ba13db2a3 in KPluginFactory::createInstance<PowerDevilKCM, QWidget> (parentWidget=<value optimized out>, parent=<value optimized out>, args=@0x7fffb4ab4970)
    at /home/kde-devel/kde/include/KDE/../kpluginfactory.h:461
#23 0x00007f6babb8f25d in KPluginFactory::create (this=0x1c6df00, iface=0x7f6bac1b0c20 "KCModule", parentWidget=0x0, parent=0x1af53f0, args=@0x7fffb4ab4970, keyword=@0x7fffb4ab4690)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/util/kpluginfactory.cpp:191
#24 0x00007f6bac45c5b6 in KService::createInstance<KCModule> (service=<value optimized out>, parent=0x1af53f0, args=@0x7fffb4ab4970, error=0x7fffb4ab4980)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/util/kpluginfactory.h:515
#25 0x00007f6bac45b604 in KCModuleLoader::loadModule (mod=@0x1c64300, report=KCModuleLoader::Inline, parent=0x1af53f0, args=@0x1c642d0)
    at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleloader.cpp:90
#26 0x00007f6bac46123a in KCModuleProxyPrivate::loadModule (this=0x1c642d0) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:107
#27 0x00007f6bac462225 in KCModuleProxy::realModule (this=<value optimized out>) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:83
#28 0x00007f6bac46234c in KCModuleProxy::buttons (this=0x5118) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmoduleproxy.cpp:300
#29 0x00007f6bac45c998 in KCMultiDialogPrivate::updateButtons (this=<value optimized out>, currentModule=0x5118) at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmultidialog.cpp:71
#30 0x00007f6bac45d801 in KCMultiDialog::addModule (this=0x1bbf470, moduleInfo=@0x7fffb4ab5660, parentItem=0x0, args=<value optimized out>)
    at /home/kde-devel/kde/src/KDE/kdelibs/kutils/kcmultidialog.cpp:342
#31 0x00007f6bac6979dc in kdemain (_argc=2, _argv=0x7fffb4ab5c88) at /home/kde-devel/kde/src/KDE/kdebase/runtime/kcmshell/main.cpp:268
#32 0x00007f6ba986a546 in __libc_start_main () from /lib/libc.so.6
#33 0x0000000000400709 in _start ()

---

I'm lazy now, but I will try to use an updated snapshot

I am using qt-copy from trunk.

After updating it and building in release mode, the problem has gone (there are no visual glitches or something like that), but it's most probably because the assert was removed in the release build.

I will recompile Qt in debug mode soon and see what happens.

Cannot reproduce on trunk r903258

Mh, here I can reproduce the crash too using todays QT4.5 snapshot (20081230). Should this bug be reported on QT bugtracker ?

*** Bug 179369 has been marked as a duplicate of this bug. ***

*** Bug 180210 has been marked as a duplicate of this bug. ***

Yeah, I think this is something for Qt guys

Also, it seems like QtDesigner crashes in the same way when previewing the "powerdevil/kcmodule/profileEditPage.ui" file.
How it should be report in the Qt bugtracker?

Well. I have reported the issue to QT. Let see what happens...
Meanwhile, closing as UPSTREAM :)

QT people can't reproduce the issue, but I noticed that this only crash when using my self compiled Qt packages... Using the default distro binary packages I can load PowerDevil and load the UI file in Designer

So it's probably a compiler optimization bug

Here I'm using:

CARCH="x86_64"
CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=native -O2 -pipe"
CXXFLAGS="${CFLAGS}"
MAKEFLAGS="-j2"

with gcc 4.3.2
and my processor is "Intel(R) Celeron(R) CPU 540  @ 1.86GHz"

Wow, this seems to go farther than I thought... Dario, suggest your opinion to Qt people, and ask them instruction for doing a test case on your compiled sources, probably there is something strange with some flags as you guessed.

Oh, and thanks for caring so much about this, I really appreciate it :)

Done :), I'm waiting for their instructions 

It is completely not related to optimization or something else. It is just a bug in Qt. As task has been open 240759 in Qt Software and i just fix the problem. I will ask for a review tomorrow and i will push the patch to qt-copy. It will be included for 4.4.4 and 4.5.0. :) keep your eyes on qt-copy.

@Alexis: bug number 240759 is the number the bugtracker assigned to my own bug report of this crash. Benjamin Poulain (Qt) sent me an e-mail saying that he couldn't reproduce the crash... and then I sent to him my discovers about the compilar flags. I'm now waiting for their answer...
Did you made a patch for it ? Great :)

*** Bug 180497 has been marked as a duplicate of this bug. ***

*** Bug 181025 has been marked as a duplicate of this bug. ***

*** Bug 181037 has been marked as a duplicate of this bug. ***

it is fixed now, on kubuntu repo