Created attachment 150603 [details] Fedora 36 upgrade transaction Many things on my system recently started printing this to stderr. It's mostly just annoying, but it does get into the stdout of `kscreen-console json` and make the json invalid, and having this warning showing up in my consoles all the time feels a bit dodgy. STEPS TO REPRODUCE 1. `kioclient5 stat` ... is the shortest command I know that prints the error and exits immediately, but it's much more widespread. OBSERVED RESULT QSocketNotifier: Can only be used with threads started with QThread kioclient5: Syntax error, not enough arguments EXPECTED RESULT kioclient5: Syntax error, not enough arguments SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora 36 KDE Plasma Version: 5.25.2 KDE Frameworks Version: 5.96.0 Qt Version: 5.15.3 ADDITIONAL INFORMATION This shows how many times the message has been logged by various programs since boot: journalctl -b --output cat --output-fields=_EXE MESSAGE='QSocketNotifier: Can only be used with threads started with QThread' | sort | uniq -c | sort -nk1,1 On my machine, it prints: 1 /usr/bin/dolphin 1 /usr/bin/korganizer 1 /usr/bin/kstart 1 /usr/bin/kwrite 1 /usr/bin/okteta 1 /usr/bin/plasma-discover 1 /usr/libexec/ksmserver-logout-greeter 2 /usr/bin/akonadi_archivemail_agent 2 /usr/bin/akonadi_birthdays_resource 2 /usr/bin/akonadi_control 2 /usr/bin/akonadi_followupreminder_agent 2 /usr/bin/akonadi_indexing_agent 2 /usr/bin/akonadi_maildispatcher_agent 2 /usr/bin/akonadi_mailfilter_agent 2 /usr/bin/akonadi_mailmerge_agent 2 /usr/bin/akonadi_migration_agent 2 /usr/bin/akonadi_newmailnotifier_agent 2 /usr/bin/akonadi_sendlater_agent 2 /usr/bin/akonadi_unifiedmailbox_agent 2 /usr/bin/akonadi_vcard_resource 2 /usr/bin/corectrl 2 /usr/bin/kalendarac 2 /usr/bin/kcminit_startup 2 /usr/bin/kded5 2 /usr/bin/ksplashqml 2 /usr/bin/kwalletd5 2 /usr/bin/plasmashell 2 /usr/libexec/baloorunner 2 /usr/libexec/DiscoverNotifier 2 /usr/libexec/kactivitymanagerd 2 /usr/libexec/kdeconnectd 2 /usr/libexec/kf5/polkit-kde-authentication-agent-1 2 /usr/libexec/org_kde_powerdevil 2 /usr/libexec/xdg-desktop-portal-kde 4 /usr/bin/akonadi_akonotes_resource 4 /usr/bin/akonadi_contacts_resource 4 /usr/bin/akonadi_ical_resource 4 /usr/bin/akonadi_maildir_resource 4 /usr/bin/systemsettings 36 /usr/bin/konsole 39 /usr/libexec/kscreenlocker_greet According to `sudo rg --one-file-system -Suu "Can only be used with threads" --binary /usr`, the message probably comes from /usr/lib64/libQt5Core.so.5.15.3, which the top culprits link against according to `ldd`, and which is provided by the qt5-qtbase package. According to `dnf history`, this package was updated from version 5.15.2-30 to version 5.15.3-1 as part of the Fedora 35->36 upgrade on 2022-05-12. I have attached the `dnf history info` from that transaction. Oddly, the logs show 59 occurances of the message from 2022-03-29, when the installed qt5-qtbase version was 5.15.2, but then it didn't appear again until many boots later on 2022-05-16, which was the SECOND (wat?) boot and login session after the Fedora 35->36 upgrade, with no intervening dnf transactions. Unfortunately, I have no logs from before 2022-03-29, because plasma-systemmonitor had some kind of fit and spammed hundreds of messages per second, which flushed the journal from before that date. I don't know whether this is a problem with libQt or with the use of it. This seems similar to bug 418402, but it has a much wider blast radius and seems to have started with a different version of qt5-qtbase.
> I don't know whether this is a problem with libQt or with the use of it. I'm CCing some very smart people who may be able to determine which one it is.
(In reply to Nate Graham from comment #1) > > I don't know whether this is a problem with libQt or with the use of it. > I'm CCing some very smart people who may be able to determine which one it > is. (In reply to Russell Haley from comment #0) > Created attachment 150603 [details] > Fedora 36 upgrade transaction > > Many things on my system recently started printing this to stderr. It's > mostly just annoying, but it does get into the stdout of `kscreen-console > json` and make the json invalid, and having this warning showing up in my > consoles all the time feels a bit dodgy. > > > STEPS TO REPRODUCE > > 1. `kioclient5 stat` > > ... is the shortest command I know that prints the error and exits > immediately, but it's much more widespread. > > OBSERVED RESULT > > QSocketNotifier: Can only be used with threads started with QThread > kioclient5: Syntax error, not enough arguments > > EXPECTED RESULT > > kioclient5: Syntax error, not enough arguments > > SOFTWARE/OS VERSIONS > > Linux/KDE Plasma: Fedora 36 > KDE Plasma Version: 5.25.2 > KDE Frameworks Version: 5.96.0 > Qt Version: 5.15.3 > > ADDITIONAL INFORMATION > > This shows how many times the message has been logged by various programs > since boot: > > journalctl -b --output cat --output-fields=_EXE > MESSAGE='QSocketNotifier: Can only be used with threads started with > QThread' | sort | uniq -c | sort -nk1,1 > > On my machine, it prints: > > 1 /usr/bin/dolphin > 1 /usr/bin/korganizer > 1 /usr/bin/kstart > 1 /usr/bin/kwrite > 1 /usr/bin/okteta > 1 /usr/bin/plasma-discover > 1 /usr/libexec/ksmserver-logout-greeter > 2 /usr/bin/akonadi_archivemail_agent > 2 /usr/bin/akonadi_birthdays_resource > 2 /usr/bin/akonadi_control > 2 /usr/bin/akonadi_followupreminder_agent > 2 /usr/bin/akonadi_indexing_agent > 2 /usr/bin/akonadi_maildispatcher_agent > 2 /usr/bin/akonadi_mailfilter_agent > 2 /usr/bin/akonadi_mailmerge_agent > 2 /usr/bin/akonadi_migration_agent > 2 /usr/bin/akonadi_newmailnotifier_agent > 2 /usr/bin/akonadi_sendlater_agent > 2 /usr/bin/akonadi_unifiedmailbox_agent > 2 /usr/bin/akonadi_vcard_resource > 2 /usr/bin/corectrl > 2 /usr/bin/kalendarac > 2 /usr/bin/kcminit_startup > 2 /usr/bin/kded5 > 2 /usr/bin/ksplashqml > 2 /usr/bin/kwalletd5 > 2 /usr/bin/plasmashell > 2 /usr/libexec/baloorunner > 2 /usr/libexec/DiscoverNotifier > 2 /usr/libexec/kactivitymanagerd > 2 /usr/libexec/kdeconnectd > 2 /usr/libexec/kf5/polkit-kde-authentication-agent-1 > 2 /usr/libexec/org_kde_powerdevil > 2 /usr/libexec/xdg-desktop-portal-kde > 4 /usr/bin/akonadi_akonotes_resource > 4 /usr/bin/akonadi_contacts_resource > 4 /usr/bin/akonadi_ical_resource > 4 /usr/bin/akonadi_maildir_resource > 4 /usr/bin/systemsettings > 36 /usr/bin/konsole > 39 /usr/libexec/kscreenlocker_greet > > According to `sudo rg --one-file-system -Suu "Can only be used with threads" > --binary /usr`, the message probably comes from > /usr/lib64/libQt5Core.so.5.15.3, which the top culprits link against > according to `ldd`, and which is provided by the qt5-qtbase package. > > According to `dnf history`, this package was updated from version 5.15.2-30 > to version 5.15.3-1 as part of the Fedora 35->36 upgrade on 2022-05-12. I > have attached the `dnf history info` from that transaction. > > Oddly, the logs show 59 occurances of the message from 2022-03-29, when the > installed qt5-qtbase version was 5.15.2, but then it didn't appear again > until many boots later on 2022-05-16, which was the SECOND (wat?) boot and > login session after the Fedora 35->36 upgrade, with no intervening dnf > transactions. Unfortunately, I have no logs from before 2022-03-29, because > plasma-systemmonitor had some kind of fit and spammed hundreds of messages > per second, which flushed the journal from before that date. > > I don't know whether this is a problem with libQt or with the use of it. > > This seems similar to bug 418402, but it has a much wider blast radius and > seems to have started with a different version of qt5-qtbase. I encountered the same phenomenon. In addition, the standard keyboard shortcuts do not work.
I ran into exactly the same issue after an upgrade in Arch Linux from plastma 5.27.6 to 5.27.7 alone with a collection of qt-related upgrade as well :(
(In reply to Nate Graham from comment #1) > > I don't know whether this is a problem with libQt or with the use of it. > I'm CCing some very smart people who may be able to determine which one it > is. @Nate Graham, can I trouble you to escalate this issue please to see if we can get some clue? I just run into this almost exactly same issue with many KDE apps impacted. This is after a seemingly harmless upgrade from plasma 5.27.6 to 5.27.7 and minor version update of qt-5.15.10 on an Arch Linux box. Thanks.
Created attachment 161323 [details] updated package list triggering this bug I am attaching the package list which I updated today that introduced this bug on my Arch Linux machine
Looks like a problem in Qt. in openSUSE KF was also updated but Qt wasn't, and I did not encounter the problem.
(In reply to P Shao from comment #3) > I ran into exactly the same issue after an upgrade in Arch Linux from > plastma 5.27.6 to 5.27.7 alone with a collection of qt-related upgrade as > well :( Forgot to add that this only appears to happen under KDE wayland sessions
(In reply to Fushan Wen from comment #6) > Looks like a problem in Qt. in openSUSE KF was also updated but Qt wasn't, > and I did not encounter the problem. Thanks for sharing the information, any clue what it might be? I can try to downgrade some packages to test to help :)
After some fiddling around through package downgrading/upgrading, I have confirmed at least on my computer it was caused by fcitx5-qt (5.0.17-7 => 5.1.0-1), which makes sense to explain why the bug impacted so many (seemingly all) qt-based applications. I will reach out to the maintainer of the package for bug report.