Comment 0 for bug 1573478

After an update 2 or 3 days ago, at random times mid-session, all window decorations vanish, then the desktop goes to black (just time/date stamp showing IIRC, as at a screen lock), and then I'm presented with a login screen again.

I was logging in with Gnome Flashback. It's been happening several times a day, and it's infuriating.

This time I've logged in with the "(Metacity)" option rather than the (Flashback)" option, and I'll see if that works. Otherwise, I'll go back to a Window Maker session to get a reliable experience.

I see this in /var/log/kern.log:

Apr 22 18:31:48 pute kernel: [11401.021438] perf interrupt took too long (2509 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
Apr 22 18:32:33 pute kernel: [11445.589519] show_signal_msg: 66 callbacks suppressed
Apr 22 18:32:33 pute kernel: [11445.589528] metacity[2447]: segfault at 1a3359 ip 0000000000426f51 sp 00007fff3ed289b8 error 4 in metacity[400000+8d000]
Apr 22 18:32:33 pute gnome-session-binary[1845]: Unrecoverable failure in required component metacity.desktop
Apr 22 18:32:47 pute gnome-session-binary[7282]: Entering running state
Apr 22 18:33:37 pute gnome-session-binary[8527]: Entering running state

Here are some earlier ones:

Apr 22 15:18:47 pute kernel: [60617.177188] metacity[16270]: segfault at 48 ip 0000000000426e2e sp 00007fff2daf0478 error 4 in metacity[400000+8d000]
Apr 22 15:18:47 pute gnome-session-binary[16198]: Unrecoverable failure in required component metacity.desktop
Apr 22 15:18:58 pute gnome-session-binary[28521]: Entering running state
Apr 22 15:21:11 pute NetworkManager[802]: <info> [1461302471.2831] ModemManager disappeared from bus
Apr 22 15:21:52 pute kernel: [ 0.000000] Initializing cgroup subsys cpuset

Apr 22 02:22:23 pute kernel: [14028.678785] show_signal_msg: 27 callbacks suppressed
Apr 22 02:22:23 pute kernel: [14028.678797] metacity[2509]: segfault at 302e64617074 ip 0000000000466780 sp 00007ffca8b8b998 error 4 in metacity[400000+8d000]
Apr 22 02:22:28 pute gnome-session-binary[2439]: Unrecoverable failure in required component metacity.desktop
Apr 22 02:22:56 pute gnome-session-binary[9411]: Entering running state
Apr 22 04:02:03 pute kernel: [20008.941872] metacity[9467]: segfault at 7f6e008e0018 ip 0000000000426e20 sp 00007ffc7090a3c8 error 4 in metacity[400000+8d000]
Apr 22 04:02:03 pute gnome-session-binary[9411]: Unrecoverable failure in required component metacity.desktop
Apr 22 04:02:23 pute gnome-session-binary[14247]: Entering running state
Apr 22 04:15:57 pute kernel: [20843.181807] traps: metacity[14309] general protection ip:466530 sp:7ffd40cb18b8 error:0 in metacity[400000+8d000]
Apr 22 04:15:57 pute gnome-session-binary[14247]: Unrecoverable failure in required component metacity.desktop
Apr 22 04:15:57 pute kernel: [20843.493120] QXcbEventReader[15628]: segfault at 7ff10d5e7629 ip 00007ff10d5e7629 sp 00007ff0ff5a5d60 error 14 in libes_plugin.so[7ff10d697000+6000]
Apr 22 04:16:16 pute gnome-session-binary[16198]: Entering running state

Apr 21 22:25:24 pute kernel: [3148119.324731] metacity[2822]: segfault at 100000007 ip 00007f8020e83278 sp 00007ffdc421c010 error 4 in libc-2.21.so (deleted)[7f8020e04000+1c0000]
Apr 21 22:25:24 pute gnome-session-binary[2714]: Unrecoverable failure in required component metacity.desktop
Apr 21 22:25:24 pute kernel: [3148119.901802] dconf worker[2727]: segfault at 8 ip 00007f35f3db2481 sp 00007f35ea99baa0 error 4 in libglib-2.0.so.0.4706.0 (deleted)[7f35f3d6b000+10e000]
Apr 21 22:25:29 pute kernel: [3148124.830996] dbus-daemon[2635]: segfault at 0 ip 00007f10b2934017 sp 00007ffff7b10518 error 6 in libdbus-1.so.3.14.6 (deleted)[7f10b2908000+4a000]
Apr 21 22:25:55 pute gnome-session-binary[19038]: Entering running state
Apr 21 22:26:28 pute gnome-session-binary[19038]: Entering running state
Apr 21 22:26:28 pute kernel: [3148183.865201] metacity[19100]: segfault at 48 ip 0000000000426f51 sp 00007ffe2a345168 error 4 in metacity[400000+8d000]
Apr 21 22:26:32 pute gnome-session-binary[19038]: Unrecoverable failure in required component metacity.desktop
Apr 21 22:26:48 pute gnome-session-binary[20075]: Entering running state
Apr 21 22:27:31 pute gnome-session-binary[20075]: Entering running state

$ lsb_release -rd
Description: Ubuntu 16.04 LTS
Release: 16.04
$ apt-cache policy metacity
metacity:
  Installed: 1:3.18.3-1ubuntu3
  Candidate: 1:3.18.3-1ubuntu3
  Version table:
 *** 1:3.18.3-1ubuntu3 500
        500 http://mirror.optus.net/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status
     1:2.34.13-0ubuntu4.1 500
        500 http://au.archive.ubuntu.com/ubuntu trusty-updates/main amd64 Packages

What I expected to happen: No spontaneous, forced logout.
What happened instead: Repeated, random forced logouts.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: metacity 1:3.18.3-1ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
CurrentDesktop: GNOME-Flashback:Unity
Date: Fri Apr 22 18:44:02 2016
InstallationDate: Installed on 2014-01-24 (819 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140123)
SourcePackage: metacity
UpgradeStatus: No upgrade log present (probably fresh install)