Bug 370913

Summary:	Logout from Wayland session locks up system
Product:	[Plasma] kwin	Reporter:	Roman Gilg <subdiff>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	major	CC:	bshah, butirsky, jodr666, monkeyboyted
Priority:	NOR	Flags:	mgraesslin: Wayland+
Version First Reported In:	git master
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Roman Gilg 2016-10-15 11:57:35 UTC

After logout via start menu, the display goes dark but never launches sddm afterwards. Also switching to other VT doesn't work anymore. You have to hard reset the machine.

In the hung up state I observed the following:
a) initiating a ssh connection to the machine doesn't work anymore, but
b) if there was already a ssh connection beforehand, you can still use it fully and I ran some commands, which could help solving this issue:

Commands: w, ps aux | grep sddm, ps aux | grep wayland, systemctl status sddm.service 
Before logout attempt: https://paste.kde.org/p73u3wypo
In locked up state: https://paste.kde.org/pw0gj3v5b

Kernel log: dmesg (!)
https://paste.kde.org/pkfxfqtu0


Reproducible: Always

Steps to Reproduce:
1. Launch Wayland session
2. Try to logout from session

Comment 1 Martin Flöser 2016-10-15 12:15:21 UTC

I have seen the problem as well, though when starting directly from vt doesn't cause the issue.

Does a restart of sddm (through ssh) fix the issue?

Comment 2 Roman Gilg 2016-10-15 12:33:51 UTC

After issuing "systemctl restart sddm" the terminal login-prompt on tty2 is displayed and you can login. But switching to other terminals via Ctrl+Alt+Fx is not possible.

Comment 3 Roman Gilg 2016-10-15 13:03:03 UTC

For comparision command output in X session:

Before logout:
https://paste.kde.org/p6u7ubyy5
After logout:
https://paste.kde.org/pjnfy00lm

A difference I noticed in the logs: In the Wayland case, the sddm-helper doesn't exit and the Greeter doesn't get stopped in the "Before logout" state. This happens instead on logout (with restart). And in Wayland it tries to create a new vt7, but that's probably meant this way, since the Wayland session doesn't take over vt7.

In this context: In the Wayland case after logout the jump to vt2 in the sddm.service logs is difficult to understand. sddm is on vt7 and Wayland was on vt8.

Comment 4 Bhushan Shah 2016-10-20 11:12:25 UTC

This I think is partly related to https://bugs.kde.org/show_bug.cgi?id=355920 as well..

Comment 5 Tony 2016-10-21 06:01:41 UTC

I've been having this mostly on my virtualbox vm install but i thought it was a virtualbox issue. On my main system, well wayland is too "unstable" on it so i gave it a pass, until now.

Comment 6 Martin Flöser 2016-11-22 14:04:22 UTC

kwin terminates correctly when this happens, but sddm-greeter crashes.

martin@martin-yoga:~$ sudo coredumpctl info sddm-greeter
           PID: 1122 (sddm-greeter)
           UID: 118 (sddm)
           GID: 125 (sddm)
        Signal: 11 (SEGV)
     Timestamp: Tue 2016-11-22 14:58:52 CET (2min 43s ago)
  Command Line: /usr/bin/sddm-greeter --socket /tmp/sddm-:0-LjVbeT --theme /usr/share/sddm/themes/breeze
    Executable: /usr/bin/sddm-greeter
 Control Group: /user.slice/user-118.slice/session-1.scope
          Unit: session-1.scope
         Slice: user-118.slice
       Session: 1
     Owner UID: 118 (sddm)
       Boot ID: bf095df81ada4eb78dee3d8467781782
    Machine ID: a8007ac462c5459ba22c27c597e11401
      Hostname: martin-yoga
      Coredump: /var/lib/systemd/coredump/core.sddm-greeter.118.bf095df81ada4eb78dee3d8467781782.1122.1479823132000000000000.xz
       Message: Process 1122 (sddm-greeter) of user 118 dumped core.
                
                Stack trace of thread 1122:
                #0  0x00007fb5778f7ac0 n/a (libKF5CoreAddons.so.5)
                #1  0x00007fb5778f1fc6 n/a (libKF5CoreAddons.so.5)
                #2  0x00007fb5778f230f _ZN9KDirWatchD1Ev (libKF5CoreAddons.so.5)
                #3  0x00007fb5778f2329 n/a (libKF5CoreAddons.so.5)
                #4  0x00007fb58f014ff8 __run_exit_handlers (libc.so.6)
                #5  0x00007fb58f015045 __GI_exit (libc.so.6)
                #6  0x00007fb58a20cac5 _XDefaultIOError (libX11.so.6)
                #7  0x00007fb59115160e ioErrorHandler (/usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.7.0)
                #8  0x00007fb58a20ccee _XIOError (libX11.so.6)
                #9  0x00007fb58a209fb2 n/a (libX11.so.6)
                #10 0x00007fb58a20a7e9 _XFlush (libX11.so.6)
                #11 0x00007fb58a20d385 _XGetRequest (libX11.so.6)
                #12 0x00007fb58a1edafc XFreePixmap (libX11.so.6)
                #13 0x00007fb58d26dff1 n/a (libGL.so.1)
                #14 0x00007fb5912f4fe6 _ZN11QGLXPbufferC2EP17QOffscreenSurface (/usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so)
                #15 0x00007fb5912f3963 _ZNK18QXcbGlxIntegration30createPlatformOffscreenSurfaceEP17QOffscreenSurface (/usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so)
                #16 0x00007fb59115a131 _ZNK15QXcbIntegration30createPlatformOffscreenSurfaceEP17QOffscreenSurface (/usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.7.0)
                #17 0x00007fb58ff20a3e _ZN17QOffscreenSurface6createEv (libQt5Gui.so.5)
                #18 0x00007fb590e5e127 n/a (libQt5Quick.so.5)
                #19 0x00007fb590e5d630 _ZN13QSGRenderLoop7cleanupEv (libQt5Quick.so.5)
                #20 0x00007fb58fbc227e _Z21qt_call_post_routinesv (libQt5Core.so.5)
                #21 0x00007fb58fbc465c _ZN16QCoreApplicationD2Ev (libQt5Core.so.5)
                #22 0x0000000000416278 main (sddm-greeter)