Panel spams system log in an infinite loop freezing the system

[RoydZeller]

Expected Behavior

• The panel works

Current Behavior

• The panel doesn't work

Possible Solution

• Make the panel work

Steps to Reproduce (for bugs)

1. Open the panel program

Context

When lxqt-panel is running, it spawns the system journal with the message
lxqt-panel[1446]: Container window visible, stack below
Hundreds of thousands of times per second freezing the system until the panel is closed.

System Information

• All the latest packages on Arch Linux on 2024 March 26th
• lxqt-panel 1.4.0-1
• libdbusmenu-qt5 0.9.3
• libqtxdg 3.12.0-3
• libxcb 1.16.1-1
• libxcomposite 0.4.6-1
• qt5-base 5.15.13

[tsujan]

Not reproducible, of course.

Which WM do you use?

[RoydZeller]

DE: lxqt-session
WM: kwin 6.0.2

[tsujan]

I also use kwin 6.0.2 but with git LXQt, which is based on Qt6.

Did you experience the same issue before upgrading to KWin 6.0.2?

[stefonarch]

Could you test with the default configuration /usr/share/lxqt/panel.conf ?
If it doesn't happen could you share your ~/.config/lxqt/panel.conf ?

[tsujan]

Hundreds of thousands of times per second

Also this can't be the case because it means hundreds of times in a millisecond ;)

[RoydZeller]

Well my journalctl log had the same line printed over 100 000 times with the same second number, for every second, anyhow
I just deleted my panel.conf to get a fresh one and it still occured immediately.
It is notable however that this happened while running under lxqt-session, but when I have plasma session in use and open lxqt-panel it does not happen.

[tsujan]

When I search "Container window visible, stack below" with google, I get only KDE bugs.

You didn't answer my second question, BTW.

[RoydZeller]

When I search "Container window visible, stack below" with google, I get only KDE bugs.

You didn't answer my second question, BTW.

I do not know as I installed lxqt-panel to try it out due to frequent crashes on xfce4-panel. I had been using mostly lxqt setup, except with kwin_x11 for WM and xfce4-panel until now.
I attempted to reset all the lxqt configuration files just now and it is appears to be immediately broken.

[RoydZeller]

Many crashes and resets later and trying to open different sets of programs, almost at the root cause.

For some reason, both lxqt-panel and lxqt-notificationd really do not like all sorts of applications that go into systray.
Notably copyq and calf seem to cause the issue here, while those 2 and ckb-next can all at complete random crash lxqt-notificationd.
I also managed to reproduce some of the error messages of the mentioned issue with these programs auto started.

Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.Menu was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.IconThemePath was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.ToolTip was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.OverlayIconName was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.IconName was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.AttentionIconName was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.OverlayIconPixmap was not found in object /StatusNotifierItem)
Mar 27 02:57:01 asd lxqt-panel[1433]: Error on DBus request(:1.78,/StatusNotifierItem): QDBusError(org.freedesktop.DBus.Error.UnknownProperty, Property org.kde.StatusNotifierItem.AttentionIconPixmap was not found in object /StatusNotifierItem)

I also went ahead and tested this with both dbus-daemon-units and dbus-broker-units, getting same results.

Some heavily cleaned up systemd journals as well.
log1.txt
log2.txt

So something has gone wildly wrong with lxqt interacting with dbus to get information about systray icons/notifications.

[stefonarch]

From the second log:

Mar 27 03:44:31 asd systemd-coredump[8041]: Process 7600 (lxqt-notificati) of user 1001 dumped core.
                                            Stack trace of thread 7600:
                                            #0  0x0000763820a7af71 n/a (libc.so.6 + 0x5cf71)
                                            #1  0x0000763820a9dba5 n/a (libc.so.6 + 0x7fba5)
                                            #2  0x00007638204b8478 n/a (libsystemd.so.0 + 0x5f478)
                                            #3  0x00007638204bae74 sd_journal_send (libsystemd.so.0 + 0x61e74)
                                            #4  0x00007638210ed7cb n/a (libQt5Core.so.5 + 0xed7cb)
                                            #5  0x00007638210e8198 n/a (libQt5Core.so.5 + 0xe8198)
                                            #6  0x00007638210e1269 n/a (libQt5Core.so.5 + 0xe1269)
                                            #7  0x000076382109836d _ZNK14QMessageLogger7warningEPKcz (libQt5Core.so.5 + 0x9836d)
                                            #8  0x0000763821f4a23d n/a (libQt5Widgets.so.5 + 0x14a23d)
                                            #9  0x000076381d05163f n/a (libKF5Notifications.so.5 + 0x2763f)
                                            #10 0x000076381d052f14 _ZN19KStatusNotifierItemC1EP7QObject (libKF5Notifications.so.5 + 0x28f14)
                                            #11 0x000076381d0d82fc n/a (KDEPlasmaPlatformTheme5.so + 0x272fc)
                                            #12 0x00007638222cdd28 _ZN15QSystemTrayIcon10setVisibleEb
....
...
 Mar 27 03:44:31 asd lxqt-notificationd[8052]: registerService failed: another service with 'org.freedesktop.Notifications' runs already

That looks like both plasma and LXQt notifications were running before.

[tsujan]

Some heavily cleaned up systemd journals as well

Referring to #2045 (comment) and the comment below it, I see problems with kscreen in your logs. That makes me suspicious of recent changes in libkscreen and libkscreen5 in Arch (read my comment below the above-mentioned link).

[RoydZeller]

I noted that in the issue lxqt/lxqt#2509 all file handles were hogged and wanted to further specify that lxqt-notificationd gave me a graphical error about this when crashing. Wasn't aware that this was a significant error since linux doesn't log such events anywhere to my knowledge.

[tsujan]

Does it still happen with Qt6 and an upgraded system?