Re: [PATCH v3 6/7] kconfig: qconf: don't show goback button on splitMode

From: Maxim Levitsky <mlevitsk@redhat.com>
To: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/7] kconfig: qconf: don't show goback button on splitMode
Date: Sat, 18 Jul 2020 22:24:24 +0300	[thread overview]
Message-ID: <e73f817c5274789d7aa59080455cf24b62acf50a.camel@redhat.com> (raw)
In-Reply-To: <d0a5ad7ddf090ff50aa486d874a8e5ab3840ea11.1593498345.git.mchehab+huawei@kernel.org>

On Tue, 2020-06-30 at 08:26 +0200, Mauro Carvalho Chehab wrote:
> the goback button does nothing on splitMode. So, why display
> it?
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  scripts/kconfig/qconf.cc | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/kconfig/qconf.cc b/scripts/kconfig/qconf.cc
> index e43fe4dcd4e7..6a327b69ff5f 100644
> --- a/scripts/kconfig/qconf.cc
> +++ b/scripts/kconfig/qconf.cc
> @@ -437,9 +437,10 @@ void ConfigList::updateList(ConfigItem* item)
>  	if (rootEntry != &rootmenu && (mode == singleMode ||
>  	    (mode == symbolMode && rootEntry->parent != &rootmenu))) {
>  		item = (ConfigItem *)topLevelItem(0);
> -		if (!item)
> +		if (!item && mode != symbolMode) {
>  			item = new ConfigItem(this, 0, true);
> -		last = item;
> +			last = item;
> +		}
>  	}
>  	if ((mode == singleMode || (mode == symbolMode && !(rootEntry->flags & MENU_ROOT))) &&
>  	    rootEntry->sym && rootEntry->prompt) {

I finally found some time to debug this.

This patch make xconfig crash when you try to select a menu that opens a submenu.

This is the backtrace:

#0  0x000000000041d196 in ConfigItem::testUpdateMenu(bool) ()
#1  0x000000000041e2f8 in ConfigList::updateList(ConfigItem*) ()
#2  0x0000000000420e3a in ConfigList::setRootMenu(menu*) ()
#3  0x00007ffff7
0f1fb0 in void doActivate<false>(QObject*, int, void**) () at /lib64/libQt5Core.so.5
#4  0x000000000041bd22 in ConfigList::menuSelected(menu*) ()
#5  0x0000000000425eb0 in
ConfigList::mouseDoubleClickEvent(QMouseEvent*) ()
#6  0x00007ffff7a9fcd1 in QWidget::event(QEvent*) () at /lib64/libQt5Widgets.so.5
#7  0x00007ffff7b483b2 in QFrame::event(QEvent*) () at
/lib64/libQt5Widgets.so.5
#8  0x00007ffff70c2d2e in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#9  0x00007ffff7a5e052 in
QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#10 0x00007ffff7a63891 in QApplication::notify(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#11
0x00007ffff70c2fc0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#12 0x00007ffff7a6278a in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*,
QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) ()
    at /lib64/libQt5Widgets.so.5
#13 0x00007ffff7ab7f82 in QWidgetWindow::handleMouseEvent(QMouseEvent*) () at /lib64/libQt5Widgets.so.5
#14
0x00007ffff7abadde in QWidgetWindow::event(QEvent*) () at /lib64/libQt5Widgets.so.5
#15 0x00007ffff7a5e063 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#16
0x00007ffff70c2fc0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#17 0x00007ffff74a7142 in
QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () at /lib64/libQt5Gui.so.5
#18 0x00007ffff748915b in
QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Gui.so.5
#19 0x00007fffe6ecdc9e in xcbSourceDispatch(_GSource*, int (*)(void*), void*) () at
/lib64/libQt5XcbQpa.so.5
#20 0x00007ffff605b7af in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#21 0x00007ffff605bb38 in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#22
0x00007ffff605bc03 in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#23 0x00007ffff710eb73 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at
/lib64/libQt5Core.so.5
#24 0x00007ffff70c191b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#25 0x00007ffff70c95a6 in QCoreApplication::exec() () at
/lib64/libQt5Core.so.5
#26 0x000000000040e553 in main ()

For example:
'Input device support'->'Keyboards'

Maybe we shoudld just revert it? I tried to understand the code a little bit,
but no luck yet to understand how the whole thing works.

Best regards,
	Maxim Levitsky