Bug 725187

Two things that happen

Option 1: I can switch user, but the interface is unusable - I can type, but not interact with any windows or alt+tab. Moving the mouse to the top left of the screen does nothing.

Option 2: black screen instead of login prompt.

This is definitely a gnome shell problem. If I kill -9 gnome-shell, everything comes back to life.

Created attachment 515922 [details]
strace -f -s 250 CRASHED-GNOME-SHELL-PID 1

Created attachment 515923 [details]
strace -f -s 250 CRASHED-GNOME-SHELL-PID 2

Hopefully this strace will help.

Again:

Process 10647 attached with 6 threads - interrupt to quit
[pid 10762] read(40,  <unfinished ...>
[pid 10655] futex(0x138241c, FUTEX_WAIT_PRIVATE, 5, NULL <unfinished ...>
[pid 10654] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 10653] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 10652] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 10647] restart_syscall(<... resuming interrupted call ...> <unfinished ...>

Still the same problem with Fedora 16.

Switching from user1 to user2 works fine.
Switching back from user2 to user1 fails.

Xorg.0.log has this:

[398851.797] (II) AIGLX: Suspending AIGLX clients for VT switch

[398875.982] (II) AIGLX: Resuming AIGLX clients after VT switch

Any chance of upping severity? I have to kill gdm and I lose my work.

I see the same here.

There are two different things that can happen if user switching fails:

a) the screen is completely black solution -> switch to another VT to find gdm, that is gdm is running fine, but the correct VT is not selected automatically. This does not happen very often.

b) gdm shows just one user entry picture and nothing else (no input fields etc.) and does not accept any input solution -> ctrl-alt-backspace restarts gdm on that particular VT. This does happen a lot more often than type a.

I think a is related to xorg and b is a problem of gnome-shell/gdm

(In reply to comment #9)
> I see the same here.
> 
> There are two different things that can happen if user switching fails:
> 
> a) the screen is completely black solution -> switch to another VT to find gdm,
> that is gdm is running fine, but the correct VT is not selected automatically.
> This does not happen very often.
> 
> b) gdm shows just one user entry picture and nothing else (no input fields
> etc.) and does not accept any input solution -> ctrl-alt-backspace restarts gdm
> on that particular VT. This does happen a lot more often than type a.
> 
> I think a is related to xorg and b is a problem of gnome-shell/gdm

Don't often see (a) but I see (b) regularly, having three users share a machine.

A colleague of mine reports problem (a) on RHEL6. I haven't seen this very often in F16.

For (b) I see just a blue screen. The login chooser is missing.

This bug seems to have disappeared! I will update in a week if it has gone.

I've been having the exact same problem since Fedora 15, and it DEFINITELY has not disappeared.  It's infuriating - I see the bug several times every single day.

The one thing I can add is it appears to start after waking the PC a few times from a suspended state.  If I shutdown every night, I can switch users to my heart's content.  As soon as I've done a few suspend/wake cycles, the bug comes back.

We fixed this upstream a while back, but I don't know if it's made it into an update.

The upstream bug report is here:

https://bugzilla.gnome.org/show_bug.cgi?id=653833

Could you please fix this bloody bug? gdm hanging while user switching. gdm can't be complicated, it's only doing one thing. Every single day I wonder why this bug is still open - it's nearly enough to make me switch to OS X!

F17: looks like you nailed it! Thanks!