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QiufuLan

Member

Registered: 2022-09-23

Posts: 1

qt6ct-kde-0.11-6 causes segmentation fault on Qt6 apps (wayland-only)

I’ve installed `qt6ct-kde-0.11-6` from the AUR, and now any Qt6‑based application (including `qt6ct` itself) crashes immediately with a segmentation fault. GDB shows the fault occurs inside `/usr/lib/libQt6Gui.so.6`.

- Qt6 package versions:
qt6-base 6.11.1-1
qt6-tools 6.11.1-3
qt6ct-kde 0.11-6

To reproduce this problem
1. The qt6ct.conf file requires the following settings.

[Appearance]
style=kvantum

2. It needs to be run in the Wayland environment (after testing, dwm, xfce, etc. x11 environments do not report errors, but in Wayland, even using startplasma-wayland will trigger a segmentation fault (and even fail to start the desktop environment properly))

- backtrace:

Thread 1 "qt6ct" received signal SIGSEGV, Segmentation fault.
0x00007ffff73033b6 in QFontconfigDatabase::setupFontEngine (this=<optimized out>, engine=<optimized out>, fontDef=...)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/unix/qfontconfigdatabase.cpp:1119
1119	       void *antialiasResource =
(gdb) bt
#0  0x00007ffff73033b6 in QFontconfigDatabase::setupFontEngine (this=<optimized out>, engine=<optimized out>, fontDef=...)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/unix/qfontconfigdatabase.cpp:1119
#1  0x00007ffff72f9982 in QFontconfigDatabase::fontEngine (this=0x55555561a8c0, f=..., usrPtr=<optimized out>)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/unix/qfontconfigdatabase.cpp:793
#2  0x00007ffff7099d4a in QFontDatabasePrivate::loadSingleEngine (script=script@entry=2, request=..., family=family@entry=0x555555dd9be0, 
    foundry=<optimized out>, style=style@entry=0x555555e29240, size=0x555555b06820)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontdatabase.cpp:777
#3  0x00007ffff709a0e6 in QFontDatabasePrivate::loadEngine (script=2, request=..., family=0x555555dd9be0, foundry=<optimized out>, 
    style=0x555555e29240, size=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontdatabase.cpp:806
#4  0x00007ffff70a6592 in operator() (__closure=__closure@entry=0x7fffffffc0f0, lookupScript=lookupScript@entry=2, 
    cacheScript=cacheScript@entry=2) at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontdatabase.cpp:2786
#5  0x00007ffff70a7b2c in QFontDatabasePrivate::findFont (req=..., script=script@entry=2, 
    preferScriptOverFamily=preferScriptOverFamily@entry=false) at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontdatabase.cpp:2807
#6  0x00007ffff70a85d2 in QFontDatabasePrivate::load (d=<optimized out>, script=2)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontdatabase.cpp:2903
#7  0x00007ffff707a903 in QFontPrivate::engineForScript (this=0x55555583d0f0, script=2)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfont.cpp:255
#8  0x00007ffff70b7860 in QFontMetrics::boundingRect (this=this@entry=0x7fffffffc4a0, ch=..., ch@entry=...)
    at /usr/src/debug/qt6-base/qtbase/src/gui/text/qfontmetrics.cpp:669
#9  0x00007fffe9de6679 in Kvantum::ThemeConfig::getThemeSpec (this=0x555555654580)
    at /usr/src/debug/kvantum/Kvantum/Kvantum/style/themeconfig/ThemeConfig.cpp:844
#10 0x00007fffe9d24dd4 in Kvantum::Style::Style (this=<optimized out>, useDark=<optimized out>, this=<optimized out>, 
    useDark=<optimized out>) at /usr/src/debug/kvantum/Kvantum/Kvantum/style/Kvantum.cpp:233
#11 0x00007fffe9dc74b5 in Kvantum::KvantumPlugin::create (this=<optimized out>, key=...)
    at /usr/src/debug/kvantum/Kvantum/Kvantum/style/KvantumPlugin.cpp:25
#12 0x00007ffff77bca3c in qLoadPlugin<QStyle, QStylePlugin> (
    loader=0x7ffff7da1be0 <QGlobalStatic<QtGlobalStatic::Holder<(anonymous namespace)::Q_QGS_loader> >::instance()::holder>, key=...)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/plugin/qfactoryloader_p.h:103
#13 QStyleFactory::create (key=...) at /usr/src/debug/qt6-base/qtbase/src/widgets/styles/qstylefactory.cpp:78
#14 0x00007ffff2c57a92 in Qt6CTProxyStyle::reloadSettings (this=this@entry=0x555555647830)
    at /usr/src/debug/qt6ct-kde/qt6ct/src/qt6ct-style/qt6ctproxystyle.cpp:52
#15 0x00007ffff2c57d7d in Qt6CTProxyStyle::Qt6CTProxyStyle (this=<optimized out>, this=<optimized out>)
    at /usr/src/debug/qt6ct-kde/qt6ct/src/qt6ct-style/qt6ctproxystyle.cpp:36
#16 0x00007ffff2c57e03 in Qt6CTStylePlugin::create (this=<optimized out>, key=...)
    at /usr/src/debug/qt6ct-kde/qt6ct/src/qt6ct-style/plugin.cpp:44
#17 0x00007ffff77bca3c in qLoadPlugin<QStyle, QStylePlugin> (
    loader=0x7ffff7da1be0 <QGlobalStatic<QtGlobalStatic::Holder<(anonymous namespace)::Q_QGS_loader> >::instance()::holder>, key=...)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/plugin/qfactoryloader_p.h:103
#18 QStyleFactory::create (key=...) at /usr/src/debug/qt6-base/qtbase/src/widgets/styles/qstylefactory.cpp:78
#19 0x00007ffff7f904d6 in Qt6CTPlatformTheme::Qt6CTPlatformTheme (this=<optimized out>, this=<optimized out>)
--Type <RET> for more, q to quit, c to continue without paging--c
    at /usr/include/qt6/QtCore/qarraydatapointer.h:358
#20 0x00007ffff7f90ce6 in Qt6CTPlatformThemePlugin::create (this=<optimized out>, key=..., params=...)
    at /usr/src/debug/qt6ct-kde/qt6ct/src/qt6ct-qtplugin/main.cpp:54
#21 0x00007ffff6e0632a in qLoadPlugin<QPlatformTheme, QPlatformThemePlugin, QList<QString>&> (
    loader=0x7ffff7565ba0 <QGlobalStatic<QtGlobalStatic::Holder<(anonymous namespace)::Q_QGS_ptLoader> >::instance()::holder>, key=...)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/plugin/qfactoryloader_p.h:103
#22 QPlatformThemeFactory::create (key=..., platformPluginPath=...)
    at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qplatformthemefactory.cpp:27
#23 0x00007ffff6dac58b in init_platform (pluginNamesWithArguments=..., platformPluginPath=..., platformThemeName=..., 
    argc=@0x7fffffffd89c: 1, argv=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qguiapplication.cpp:1398
#24 QGuiApplicationPrivate::createPlatformIntegration (this=0x55555560c430)
    at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qguiapplication.cpp:1616
#25 0x00007ffff6dae228 in QGuiApplicationPrivate::createEventDispatcher (this=<optimized out>)
    at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qguiapplication.cpp:1634
#26 0x00007ffff6589175 in QCoreApplicationPrivate::init (this=this@entry=0x55555560c430)
    at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:870
#27 0x00007ffff6dae32b in QGuiApplicationPrivate::init (this=this@entry=0x55555560c430)
    at /usr/src/debug/qt6-base/qtbase/src/gui/kernel/qguiapplication.cpp:1667
#28 0x00007ffff76fe876 in QApplicationPrivate::init (this=0x55555560c430)
    at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:473
#29 0x00007ffff76fe9e3 in QApplication::QApplication (this=<optimized out>, argc=<optimized out>, argv=<optimized out>, 
    this=<optimized out>, argc=<optimized out>, argv=<optimized out>)
    at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:461
#30 0x0000555555567bbb in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/qt6ct-kde/qt6ct/src/qt6ct/main.cpp:40
(gdb) 

ajgringo619

Member

Registered: 2023-05-06

Posts: 55

Re: qt6ct-kde-0.11-6 causes segmentation fault on Qt6 apps (wayland-only)

I can't reproduce this (Hyprland). Here is my current appearance section on ~/.config/qt6ct/qt6ct.conf:

[Appearance]
color_scheme_path=/home/ajgringo619/.local/share/color-schemes/DankMatugen.colors
custom_palette=true
icon_theme=BeautyLine
standard_dialogs=xdgdesktopportal
style=Fusion

I also can't permanently set style to Kvantum; setting is ignored until I start the GUI. When I bring up the GUI, I only have style options for "Fusion" or "Windows".
All of my Qt versions match yours.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,823

Re: qt6ct-kde-0.11-6 causes segmentation fault on Qt6 apps (wayland-only)

https://bbs.archlinux.org/viewtopic.php?id=313797

fc-cache -r

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