| Summary: | Logging out of Plasma 5.27.3 on Wayland resulted in a black screen | ||
|---|---|---|---|
| Product: | [Plasma] ksmserver | Reporter: | Matt Fagnani <matt.fagnani> |
| Component: | general | Assignee: | David Edmundson <kde> |
| Status: | RESOLVED UPSTREAM | ||
| Severity: | normal | CC: | fabian, kparal, nate, plasma-bugs, postix, z273ap4t |
| Priority: | NOR | ||
| Version: | 5.27.3 | ||
| Target Milestone: | --- | ||
| Platform: | Fedora RPMs | ||
| OS: | Linux | ||
| URL: | https://github.com/sddm/sddm/pull/1701 | ||
| Latest Commit: | Version Fixed In: | SDDM 0.20 | |
| Attachments: | Journal for boot of Fedora-KDE-Live-x86_64-38-20230318.n.0.iso in a QEMU/KVM VM in GNOME Boxes in which the black screen happened 3 times | ||
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Description
Matt Fagnani
2023-03-18 23:01:03 UTC
I reproduced the black screen problem when logging out as the second user in my Fedora 38 installation. loginctl in the VT showed that the second user's session was still active and there wasn't a sddm session. The problem might involve the second user's session not being properly stopped so that the sddm session never started. The errors I reported might have prevented the second user's session from stopping. xdg-desktop-portal-kde crashes when run by sddm happened as at https://bugzilla.redhat.com/show_bug.cgi?id=2129479 when I logged out as the first user and the black screen didn't happen. Bug in SDDM, fixed upstream: https://github.com/sddm/sddm/issues/1660 (In reply to Fabian Vogt from comment #2) > Bug in SDDM, fixed upstream: https://github.com/sddm/sddm/issues/1660 This problem still happened after I updated to sddm-0.19.0^git20230320.e07e805-2.fc38 https://koji.fedoraproject.org/koji/buildinfo?buildID=2172984 in my Fedora 38 KDE Plasma installation, rebooted twice, then logged in as the second user and logged out. sddm-0.19.0^git20230320.e07e805-2.fc38 appears to have the commit https://github.com/sddm/sddm/commit/e07e805c21310572b4fecc810fd5610b1d3d03fd which was marked as fixing https://github.com/sddm/sddm/issues/1660 for the user switching problem. This logout problem might be different from that one and might not be fixed yet. I was logged in as only one user when the black screen problem happened during logout. I wasn't switching users which was disabled as an option from the Leave menu of the Application Launcher menu in Fedora 38 due to the problem at https://bugs.kde.org/show_bug.cgi?id=466118 The second users on the installation and VM had the standard account type in System Settings' User page. The first users had the administrator account type in System Settings' User page and were in the wheel group. Reopening this bug, it's still not fixed. The downstream Fedora bug contains backtraces of the live sddm processes when this issue happens. Please see https://bugzilla.redhat.com/show_bug.cgi?id=2179591#c34 and below. Thanks. > This logout problem might be different from that one and might not be fixed yet. Yeah, looks like it :-/ (In reply to Kamil Paral from comment #5) > Reopening this bug, it's still not fixed. The downstream Fedora bug contains > backtraces of the live sddm processes when this issue happens. Please see > https://bugzilla.redhat.com/show_bug.cgi?id=2179591#c34 and below. Thanks. Ok. What I see is that sddm-helper sent the SESSION_STATUS command to the daemon and waits for the reply. The daemon is idle in the event loop though. If the user's session isn't stopped properly due to the failure of dbus-:1.2-org.kde.LogoutPrompt which runs /usr/libexec/ksmserver-logout-greeter from /usr/share/dbus-1/services/org.kde.LogoutPrompt.service, then the sddm session might not be started and sddm might be left waiting indefinitely, I'm reassigning this report to ksmserver due to that error and the failure of the user session to stop and the sddm session to start. This black screen problem happened most of the time I've logged out as the second and third users which were of the standard account type in my Fedora 38 installation. A race condition might be involved. This problem was accepted as a Fedora 38 Final blocker https://bugzilla.redhat.com/show_bug.cgi?id=2179591#c23 By pure chance I tried pam_lastlog2 with sddm today and that's the first time I actually ran into the issue. That was not just a coincidence - it was the "Last login: ..." message which triggers the race condition. Previously, we didn't have any PAM module printing such a message active, so sddm-helper did not end up triggering the race condition in sddm. Please try https://github.com/sddm/sddm/pull/1701. I updated to sddm-0.19.0^git20230403.67b8e4c-1.fc38.x86_64 https://bugzilla.redhat.com/show_bug.cgi?id=2179591#c39 to test the new patch. Logout of Plasma as the second user on the system happened normally 8/8 times. The black screen problem didn't happen. The user's session stopped and the sddm session started. The dbus-:1.2-org.kde.LogoutPrompt@0.service failures and other errors were still shown in the journal. Thanks. Yay! Closing as fixed upstream. *** Bug 468464 has been marked as a duplicate of this bug. *** *** Bug 474832 has been marked as a duplicate of this bug. *** |