I have the same issues on Fedora 20 64-bit Using Gnome 3.12.2 via R. Hughes COPR.

Usually the first 1-2 times I switch between users thngs works for me, but then I end up with default grey background without a user list. The behavior is identical with the one stated above.

I switched to another tty with ctrl + alt + f2 and back and then the lock screen (the "curtain") appeared. I could then login normally.

The journal displayed follwoing messages afterwards :

kvě 18 23:42:16 bumbrlicek gdm-password][7653]: gkr-pam: couldn't unlock the login keyring.
kvě 18 23:42:19 bumbrlicek gdm[761]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
kvě 18 23:42:22 bumbrlicek gdm-password][7660]: The gnome keyring socket is not owned with the same credentials as the user login: /run/user/1000/keyring/control
kvě 18 23:42:22 bumbrlicek gdm-password][7660]: gkr-pam: couldn't unlock the login keyring.
kvě 18 23:42:22 bumbrlicek gdm[761]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
kvě 18 23:42:22 bumbrlicek gnome-session[1576]: Gjs-Message: JS LOG: loading user theme: /usr/share//themes/Ceti/gnome-shell/gnome-shell.css
kvě 18 23:42:22 bumbrlicek gnome-session[1576]: Gjs-Message: JS LOG: foo
kvě 18 23:42:22 bumbrlicek gnome-session[1576]: ** (nautilus:1845): WARNING **: Can not determine workarea, guessing at layout
kvě 18 23:42:27 bumbrlicek gnome-session[1576]: (gnome-shell:1723): St-CRITICAL **: _st_create_shadow_material: assertion 'src_texture != COGL_INVALID_HANDLE' failed

kvě 18 23:42:28 bumbrlicek gnome-session[1576]: (gnome-shell:1723): Gjs-WARNING **: JS ERROR: Error: Trying to remove invalid content: [object instance proxy GIName:Meta.Background jsobj@0x7f634fbb1790 native@0
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: BackgroundCache<._removeContent@resource:///org/gnome/shell/ui/background.js:117
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: BackgroundCache<.removeImageContent@resource:///org/gnome/shell/ui/background.js:132
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: Background<._destroy@resource:///org/gnome/shell/ui/background.js:369
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: BackgroundManager<.destroy@resource:///org/gnome/shell/ui/background.js:742
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: WorkspaceThumbnail<._onDestroy@resource:///org/gnome/shell/ui/workspaceThumbnail.js:493
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: WorkspaceThumbnail<.destroy@resource:///org/gnome/shell/ui/workspaceThumbnail.js:471
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: ThumbnailsBox<._destroyThumbnails@resource:///org/gnome/shell/ui/workspaceThumbnail.js:900
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _emit@resource:///org/gnome/gjs/modules/signals.js:124
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: Overview<._hideDone@resource:///org/gnome/shell/ui/overview.js:665
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _addHandler/params[name]@resource:///org/gnome/shell/ui/tweener.js:89
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _callOnFunction@resource:///org/gnome/gjs/modules/tweener/tweener.js:203
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _updateTweenByIndex@resource:///org/gnome/gjs/modules/tweener/tweener.js:333
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _updateTweens@resource:///org/gnome/gjs/modules/tweener/tweener.js:345
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _onEnterFrame@resource:///org/gnome/gjs/modules/tweener/tweener.js:360
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: _emit@resource:///org/gnome/gjs/modules/signals.js:124
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: ClutterFrameTicker<._onNewFrame@resource:///org/gnome/shell/ui/tweener.js:206
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: wrapper@resource:///org/gnome/gjs/modules/lang.js:169
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: ClutterFrameTicker<._init/<@resource:///org/gnome/shell/ui/tweener.js:181
kvě 18 23:42:28 bumbrlicek gnome-session[1576]: Varování správce oken: Log level 16: AT-SPI: Error in GetItems, sender=org.freedesktop.DBus, error=The name :1.14 was not provided by any .service files
kvě 18 23:42:32 bumbrlicek fprintd[7345]: ** Message: No devices in use, exit
kvě 18 23:42:34 bumbrlicek gnome-session[5478]: (gnome-settings-daemon:5578): GnomeDesktop-WARNING **: Failed to acquire idle monitor proxy: Časový limit vypršel

Sometimes - after a I switch to another user, my monitor goes dark as it would loose a signal from a grapic-card.

Looked in the logs and found several appearances of :

GnomeDesktop-WARNING **: Failed to acquire idle monitor proxy: Timeout
GnomeDesktop-WARNING **: Error setting property 'PowerSaveMode' on interface org.gnome.Mutter.DisplayConfig: Timeout (g-io-error-quark, 24)
gdm-Xorg-:5[11406]: (II) AIGLX: Suspending AIGLX clients for VT switchgdm-Xorg-:1[5036]: (II) AIGLX: Resuming AIGLX clients after VT switch
gdm-Xorg-:1[5036]: (II) intel(0): switch to mode 1920x1080@60.0 on HDMI2 using pipe 0, position (0, 0), rotation normal, reflection none

I have exactly this problem in an up-to-date Arch Linux installation (gdm 3.12.2-1 for the record). In my case the problem occurs randomly, and sometimes gdm works as expected for a day or two; on average I get this once or twice a day. Despite my efforts I've not been able to reproduce it, it is really frustrating. This is a fairly recent install, and 3.12.2-1 is the only version of GDM that has been installed on my system, so I can't say whether or not this problem is specific to this version.

The logs are unremarkable (if someone is interested I can upload some logs entries immediately before and after an episode). After I've set Enable=true in the [debug] section in /etc/gdm/custom.conf, the only meaningful error I've seen is:

GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

but I don't think it is related since I see it even when GDM works normally. Sigh :( Now I'm waiting for more episodes to happen so I can collect logs. 

Probably not relevant, but I have an Intel integrated graphic card.

Also Arch Linux (3.12.2-1) and also problems.

First login after start is ok.
Upon relogin after sleep or userchange gdm screen freezes with this log:

nb gdm-password][20385]: The gnome keyring socket is not owned with the same credentials as the user login: /run/user/1000/keyring/control
nb gdm-password][20385]: gkr-pam: couldn't unlock the login keyring.
nb gdm[406]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

I've observed the same behavior.  It's been intermittent with past versions of GDM and Gnome Shell on Archlinux for my PC.  My PC includes and AMD processor and AMD video card.  There is nothing intriguing in the logs (debug not enabled).  Another interesting thing, the user list appears to be present with clicking of the mouse.  It appears as if the background image is drawn on top of the user list.  In fact, the user list appears to operate correctly, with selecting user, typing password and logging in the additional user. 

Is there a way to change the layering of the user list and background image as a test?  Maybe change background image for a partly transparent image and see if problem ever occurs?

Same problem here, and I have an nvidia card running Arch Linux (3.12.2-1).  Using journalctl shows me these two log messages repeated about 800 times at the instant that the user list first fails to show:

Aug 24 21:36:48 dan-desktop gnome-session[704]: (gnome-shell:846): St-CRITICAL **: _st_paint_shadow_with_opacity: assertion 'shadow_material != COGL_INVALID_HANDLE' failed
Aug 24 21:36:48 dan-desktop gnome-session[704]: (gnome-shell:846): Clutter-WARNING **: ./clutter-offscreen-effect.c:207: Unable to create an Offscreen buffer

*** Bug 735554 has been marked as a duplicate of this bug. ***

Demonstration: http://jeff.ecchi.ca/public/gdm-735554.webm

In that video, when I'm moving the mouse around in circles on the gray
background, it's just to indicate that the computer is not frozen. When I'm
hitting keys on the upper-left corner, I'm actually doing ctrl+alt+F1/F2/F3.



The way to reproduce this for me is to have two system user accounts, and to repeatedly try to "switch user" between them. You can also try doing a "logout" from the 2nd account for fun, as it can also trigger the bug sometimes, IIRC. Even "normal" use (ie not nekohayo "torture testing"), where you only switch accounts once or twice per day, can get you into this deadlock situation.

Sometimes switching VTs (ctrl+alt+F1/F2/F3/etc.) allows you to go back to the previous user account (in which case you may see the password prompt and then the screen shield falling down), but not always. I recall having had to resort to complete reboots, more than once.

This issue remains for me in 3.14, even with a new install.  Any updates?

I can reproduce it in 3.14 too. I simply switched users, logged back in, and when switching users again the user list is blank, and intermittently comes back when pressing any key.

*** Bug 741492 has been marked as a duplicate of this bug. ***

For me this issue started during this autumn, not sure when. Maybe after update to gnome 3.14. And it can be reproduced every time.

Currently using 3.14.1-2 in Arch

This is quite annoying, we have 5 users using this same PC and currently we always need to reboot. Well, good side is that there is no need to swap with this "kind of single user gnome mode".

(In reply to comment #11)
> For me this issue started during this autumn, not sure when. Maybe after update
> to gnome 3.14. And it can be reproduced every time.
> 
> Currently using 3.14.1-2 in Arch
> 
> This is quite annoying, we have 5 users using this same PC and currently we
> always need to reboot. Well, good side is that there is no need to swap with
> this "kind of single user gnome mode".

Also using Arch. I observed this behaviour on GDM started right after upgrading Xorg to 1.16.x

I have these exact same symptoms with CentOS 7 running its default Gnome 3.8.4.

I've documented more details on how I can easily reproduce this problem in my CentOS 7 bug report here:
https://bugs.centos.org/view.php?id=8113

One useful thing I've discovered is that running this command as root will remove the borked grey login screen:
pkill -f pam/gdm-launch-environment
and let you use the Switch User login screen again.  But this is only a weak workaround, the next time a login screen is abandoned the problem will recur.

When I investigated this before, it seems like the SessionActive signal was being dropped on the floor sometimes, and I wasn't able to figure out why. I do wonder if we're leaking DBus signal connections -- I remember something about having too many open things causing NetworkManager to stop sending / receiving signals.

I can reproduce it with a clean boot, so I wouldn't expect to have an abnormally large number of things open.

I also forgot to mention that 'systemctl status gdm' is an easy way to view a list of your displays.  You can use this command to verify that 'pkill -f pam/gdm-launch-environment' kills off the last display.

This should be fixed now I think:

https://git.gnome.org/browse/gdm/commit/?id=7295b0ab4a06f901ed4c3e2f4c77d23192c43d46

I'm still seeing this (or something similar).  I have ArchLinux with Gnome 3.14 and GDM 3.14.1.  I installed this patch and recompiled / reinstalled.  However, this issue persisted after a reboot.  After several user switches and log-in / log-out, I had this issue.  When it occurred, I had done the following:

Power On     (GDM - TTY1)
Login User A (Gnome Shell - TTY1)
Switch User  (GDM - TTY2)
Login User B (Gnome Shell - TTY2)
Switch User  (GDM - TTY3)
Login User A (Gnome Shell - TTY1)
Logout User A (GDM - TTY1)
Login User C (Gnome-Shell - TTY1)
Logut User C (GDM - TTY1)
Login User C (Gnome-Shell TTY1)
Switch User  (GDM - TTY7)
Login User B (Gnome-Shell - TTY2)
Switch User  (GDM - TTY7)  --- GREY SCREEN

Kinda of interesting that there was suddenly two GDM instances... Perhaps this is related?

Ken Jernigan, the steps below will always reproduce the problem for me on CentOS 7.  Do the same steps work for you?

1. Boot up your PC to its login screen
    -You currently have only one graphical Display 0/TTY1 at CTRL-ALT-F1
    -I.e. Display 0 is your login screen
2. Login as user1 (or whatever your first username is)
    -At this point you still have only one graphical Display 0/TTY1 at CTRL-ALT-F1
    -The login display is now user1's display
3. From the Gnome3 username menu click "Switch User"
    -At this point you have a second graphical Display 1/TTY2, most likely at CTRL-ALT-F2
    -This is a new login display
4. Login as user1 again
    -At this point you still have a second (abandoned) graphical Display 1/TTY2 (most likely at CTRL-ALT-F2) that is now borked (you just don't realize it yet)
    -Login Display 1/TTY2 was not re-used for user1 since user1 already had an active display
    -Instead your PC switched to Display 0/TTY1 which is user1's pre-existing display (i.e. the user switch worked ok)
5. From the Gnome3 username menu click "Switch User"
    -At this point you switch back to abandoned login graphical Display 1/TTY2 (most likely at CTRL-ALT-F2), but it's now a useless blank grey screen

For me the the problem only occurs when the login screen is not re-used as a user's screen (i.e. when the login screen is abandoned).  The above steps are the simplest way for me to recreate it.  At https://bugs.centos.org/view.php?id=8113 I document the steps for a more realistic use case way to invoke the problem.

I use 'systemctl status gdm' to view my list of displays and 'pkill -f pam/gdm-launch-environment' to kill the borked display (and restore Switch User functionality).

Switching users is still completely unreliable with gdm 3.16.1 - switching users a couple of times blanks the screen completely, the users are still logged in but I must use CTRL-ALT-F$(display number) to access their sessions again.

This is pretty easy to reproduce, but nowadays the user list always comes back after a few seconds. When I experienced this bug in the past, I believe the user list would not reappear.

GNOME is going to shut down bugzilla.gnome.org in favor of  gitlab.gnome.org.
As part of that, we are mass-closing older open tickets in bugzilla.gnome.org
which have not seen updates for a longer time (resources are unfortunately
quite limited so not every ticket can get handled).

If you can still reproduce the situation described in this ticket in a recent
and supported software version, then please follow
  https://wiki.gnome.org/GettingInTouch/BugReportingGuidelines
and create a new ticket at
  https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/

Thank you for your understanding and your help.