Bug 2338761

Created attachment 2075029 [details]
Journal of Plasma startup with Xwayland has crashed notification and debugging enabled

The Xwayland has crashed notification appears to be from XwaylandLauncher::handleXwaylandFinished https://invent.kde.org/plasma/kwin/-/blob/master/src/xwayland/xwaylandlauncher.cpp#L270

void XwaylandLauncher::handleXwaylandFinished(int exitCode, QProcess::ExitStatus exitStatus)
{
    qCDebug(KWIN_XWL) << "Xwayland process has quit with exit status:" << exitStatus << "exit code:" << exitCode;

#if KWIN_BUILD_NOTIFICATIONS
    KNotification::event(QStringLiteral("xwaylandcrash"), i18n("Xwayland has crashed"));
#endif

In Plasma 6.2.90 in a VM, I put QT_LOGGING_RULES="*.debug=true;qt*.debug=false" in /etc/environment and I restarted Plasma until the Xwayland has crashed notification was shown. There was a fatal server error in Xwayland "Cannot write display number to fd 72", kwin failed to establish the the XCB connection, and Xwayland quit with the code 1.

Jan 21 23:22:47 kwin_wayland_wrapper[9053]: (EE)
Jan 21 23:22:47 kwin_wayland_wrapper[9053]: Fatal server error:
Jan 21 23:22:47 kwin_wayland_wrapper[9053]: (EE) Cannot write display number to fd 72
Jan 21 23:22:47 kwin_wayland_wrapper[9053]: (EE)
Jan 21 23:22:47 kwin_wayland[8992]: kwin_xwl: Failed to establish the XCB connection (error 1)
Jan 21 23:22:47 kwin_wayland[8992]: kwin_xwl: Xwayland process has quit with exit status: QProcess::NormalExit exit code: 1

Xwayland didn't create a core dump. I'm attaching the journal from the Plasma session with the Xwayland has crashed notification.

*** Bug 2343580 has been marked as a duplicate of this bug. ***

This is proposed as a Final blocker per "There must be no SELinux denial notifications or crash notifications on boot of or during installation from a release-blocking live image, or at first login after a default install of a release-blocking desktop" - https://fedoraproject.org/wiki/Fedora_42_Final_Release_Criteria#SELinux_and_crash_notifications . With this bug, about 1/3 to 1/4 of the time, you see such a notification when starting KDE.

kwin-6.2.91-2.fc42 failed to build with the backport with errors indicating the requested version 6.2.91 didn't match 6.2.90 in the f42 repo https://kojipkgs.fedoraproject.org//work/tasks/3455/128853455/build.log
...
CMake Warning at CMakeLists.txt:154 (find_package):
  Could not find a configuration file for package "Plasma" that is compatible
  with requested version "6.2.91".
  The following configuration files were considered but not accepted:
    /usr/lib64/cmake/Plasma/PlasmaConfig.cmake, version: 6.2.90
    /lib64/cmake/Plasma/PlasmaConfig.cmake, version: 6.2.90
CMake Error at CMakeLists.txt:161 (find_package):
  Could not find a configuration file for package "KDecoration3" that is
  compatible with requested version "6.2.91".
  The following configuration files were considered but not accepted:
    /usr/lib64/cmake/KDecoration3/KDecoration3Config.cmake, version: 6.2.90
    /lib64/cmake/KDecoration3/KDecoration3Config.cmake, version: 6.2.90
-- Configuring incomplete, errors occurred!
error: Bad exit status from /var/tmp/rpm-tmp.JRzD9Y (%build)

This problem might be because the 6.2.91 update was gated by the failed test with Discover crashing and then it was unpushed due to the f42 branching. https://bodhi.fedoraproject.org/updates/FEDORA-2025-c1d22427c2 Building kwin in the side tag f42-build-side-104195 kwin-6.2.91-1.fc42 was built in might avoid those errors. https://koji.fedoraproject.org/koji/buildinfo?buildID=2646632

Yes, I know. I didn't bother building it on the side tag due to branching. The update has been unpushed now we've branched, and I don't know if we're planning to repush it or create a new one.

This bug appears to have been reported against 'rawhide' during the Fedora Linux 42 development cycle.
Changing version to 42.

This problem was fixed in kwin 6.3.0 by the patch of Vlad Zahorodnii at https://bugs.kde.org/show_bug.cgi?id=498837#c12