Bug 436024 - [Wayland] multiple screen segfault
Summary: [Wayland] multiple screen segfault
Status: RESOLVED DUPLICATE of bug 431388
Alias: None
Product: plasmashell
Classification: Plasma
Component: generic-multiscreen (show other bugs)
Version: 5.21.4
Platform: Gentoo Packages Linux
: NOR crash
Target Milestone: 1.0
Assignee: Aleix Pol
Keywords: wayland
Depends on:
Reported: 2021-04-21 22:16 UTC by Anthony Delannoy
Modified: 2021-08-24 13:52 UTC (History)
6 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:

Coredumps (32.54 KB, text/x-log)
2021-04-21 22:16 UTC, Anthony Delannoy

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Description Anthony Delannoy 2021-04-21 22:16:24 UTC
Created attachment 137773 [details]


Hi, i'm currently experiencing segfaults when i try to use multiple screen with
my KDE 5.21.4 on wayland. Reproducible 100% time, i put coredump in attachments to help debugging. 

Let me know if i can do something to help.

Thanks for your help and work on kde ! 

1. Plug another screen


Segfault, seems to be linked to libffi.so usage. See coredump attachements.


Multiple screen OK

Linux/KDE Plasma: Gentoo 64bit
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.81.0
Qt Version: 5.15.2

Comment 1 Méven Car 2021-04-22 05:56:38 UTC
Your codedump lacks debug symbols but we can see the culprit nonetheless:

#2  0x00007fc93a28dda5 _ZN9QtWayland9wl_output15handle_geometryEPvP9wl_outputiiiiiPKcS5_i (libQt5WaylandClient.so.5 + 0xb6da5)

I suspect a newer version of Qt would help.
Comment 2 Nate Graham 2021-04-22 15:23:29 UTC
Was this fixed in Qt 5.15.3 or something? Or with the KDE patch collection?
Comment 3 Anthony Delannoy 2021-04-22 16:03:54 UTC
I just checked qt5 repo and site.

The v5.15.3 and future v5.15.4 are commercial-only. I do not have access to them and v6.x.y are not yet in gentoo repo

KDE patchset are in https://invent.kde.org/qt/qt/qtbase/-/tree/5.15 ?
Comment 4 Nate Graham 2021-04-22 18:17:49 UTC
Yep, all the repos in https://invent.kde.org/qt.
Comment 5 Anthony Delannoy 2021-04-24 09:08:37 UTC
I'm looking for info and it seems to be an old bug, did not find how to fix it yet:

Comment 6 Andreas Sturmlechner 2021-04-24 17:33:25 UTC
Qt 5.15 stable branch ebuilds (5.15.9999) are available in Gentoo's qt overlay and they are pulling from KDE's kde/5.15 branch for some time already.

Comment 7 Anthony Delannoy 2021-04-25 11:51:09 UTC
Just tried this overlay, issue is still here.

If i plug another screen a lot of things segfault and desktop becomes unusable, still caused by handle_geometry.
Comment 8 Marco Martin 2021-08-24 13:48:50 UTC

                Stack trace of thread 1126:
                #0  0x00007fc93d5eead1 raise (libc.so.6 + 0x38ad1)
                #1  0x00007fc93d5eeb50 n/a (libc.so.6 + 0x38b50)
                #2  0x00007fc93a28dda5 _ZN9QtWayland9wl_output15handle_geometryEPvP9wl_outputiiiiiPKcS5_i (libQt5WaylandClient.so.5 + 0xb6da5)
                #3  0x00007fc93a144d2d n/a (libffi.so.7 + 0x6d2d)
                #4  0x00007fc93a1442b9 n/a (libffi.so.7 + 0x62b9)
                #5  0x00007fc93ed9d112 n/a (libwayland-client.so.0 + 0x9112)
                #6  0x00007fc93ed9997a n/a (libwayland-client.so.0 + 0x597a)
                #7  0x00007fc93ed9b02c wl_display_dispatch_queue_pending (libwayland-client.so.0 + 0x702c)
                #8  0x00007fc93a254296 _ZN15QtWaylandClient15QWaylandDisplay13flushRequestsEv (libQt5WaylandClient.so.5 + 0x7d296)
                #9  0x00007fc93a28ebe0 n/a (libQt5WaylandClient.so.5 + 0xb7be0)
                #10 0x00007fc93dc24d7c n/a (libQt5Core.so.5 + 0x287d7c)
                #11 0x00007fc93dc283cd _ZN15QSocketNotifier9activatedE17QSocketDescriptorNS_4TypeENS_14QPrivateSignalE (libQt5Core.so.5 + 0x28b3cd)
                #12 0x00007fc93dc28b50 _ZN15QSocketNotifier5eventEP6QEvent (libQt5Core.so.5 + 0x28bb50)
                #13 0x00007fc93e8650ff _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5 + 0x1630ff)
                #14 0x00007fc93dbf5eb8 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 + 0x258eb8)
                #15 0x00007fc93dc43dee n/a (libQt5Core.so.5 + 0x2a6dee)
                #16 0x00007fc93c906cdb g_main_context_dispatch (libglib-2.0.so.0 + 0x52cdb)
                #17 0x00007fc93c906f88 n/a (libglib-2.0.so.0 + 0x52f88)
                #18 0x00007fc93c90703f g_main_context_iteration (libglib-2.0.so.0 + 0x5303f)
                #19 0x00007fc93dc433bb _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2a63bb)
                #20 0x00007fc93dbf4963 _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x257963)
                #21 0x00007fc93dbfc300 _ZN16QCoreApplication4execEv (libQt5Core.so.5 + 0x25f300)
                #22 0x0000562a9bcfc1b5 n/a (kded5 + 0x71b5)
                #23 0x00007fc93d5d9bba __libc_start_main (libc.so.6 + 0x23bba)
                #24 0x0000562a9bcfc38a n/a (kded5 + 0x738a)
Comment 9 David Edmundson 2021-08-24 13:52:06 UTC

*** This bug has been marked as a duplicate of bug 431388 ***