Bug#973474: gnome: Unable to log back in in after screen lock

[Marcin Owsiany]

Hello again,

sob., 27 lut 2021 o 22:28 Simon McVittie <smcv at debian.org> napisał(a):

> <https://people.debian.org/~smcv/973474/> (and then after pressing Enter
> for my test user's password, I'm back to my unlocked session, equivalent
> to <https://people.debian.org/~smcv/973474/5.png>). At what point does
> what you see diverge from that?
>

See the files {1,2,3,4}-*.png in https://people.debian.org/~porridge/ which
illustrate what happens step by step when I try to unlock.


> Given that you see messages from Xorg, I would also expect to see more
> messages than just those. Before locking the screen, please run
>
>     logger "before locking"
>
> to leave a marker in the system log; and then please look back through
> the system log at least as far as that marker.
>

Today I managed to reproduce the bug by doing the following:
- boot the VM
- log into the "Cinnamon" session
- log out
- log into the "Gnome" session
- run `logger "before lock"` via ssh into the VM
- lock screen
- try to unlock

This is the contents of journal (from `sudo journalctl`) between the logger
line and the message produced when trying to unlock:
http://paste.debian.net/1187416/

If you look at the systemd journal (as root) instead of syslog, you'll
> also see "auth" messages, which could be relevant: for instance, when
> you enter a wrong password, that should be logged as an "auth" message
> from PAM.
>
> Please describe the steps you took to install your test VM, including
> any non-default settings used? For example, I wonder whether this is
> locale-sensitive - I'm using en_GB.UTF-8 but you seem to be using a
> non-English locale.
>

I installed from debian-bullseye-DI-alpha3-amd64-netinst.iso in
virt-manager VM with 2 VCPUs and 4GB of RAM.
Other than selecting Polish locale and installing ssh server and all
possible display managers and window environments that debian-installer
allows I don't remember doing anything special.


> If your test VM does not contain any personal or confidential data,
> and you can can transfer files off it with ssh, a shared filesystem or
> paste.debian.net, it would be useful to see the entire systemd journal
> (starting from boot) for this procedure:
>
> - boot the VM
> - log in as a user
> - lock the screen
> - unlock with a correct password
>
> and compare it with
> <https://people.debian.org/~smcv/973474/journalctl_-b.log.gz>.
>

So as mentioned before the above is not enough to reproduce the bug for me
either.
But I rebooted the VM and tried to reproduce again using the steps I
mentioned above, in order to grab a clean log from boot.
I also ran "logger" commands at a few steps to make the log easier to read,
and... this time the problem did not appear.
My gut feeling is that the additional switching to and from an ssh session
to run these commands slowed me down a little, and the changed timing was
enough for some leftover process from the Cinnamon session to disappear
before I locked the screen.
To verify, I subsequently (without rebooting the VM) logged into and out of
Cinnamon session once more, and then logged into the GNOME session again
(without running the logger commands this time), and WAS able to reproduce
the issue.

I have a full output of journalctl for that run of the VM, at
https://people.debian.org/~porridge/journal.txt.gz


> > Is there perhaps some setting I could tweak to convince gnome-shell to
> produce
> > some debug output when I attempt unlocking?
>
> Try these:
>
> systemctl --user edit gnome-shell at x11.service
> systemctl --user edit gnome-shell at wayland.service
> sudo systemctl edit gdm.service
>
> and in each case, add this:
>
> [Service]
> Environment=G_MESSAGES_DEBUG=all
>

I also attempted to increase verbosity level with the commands you
provided, but the first two ones failed for me:
porridge at debian:~$ systemctl --user edit gnome-shell at x11.service
No files found for gnome-shell at x11.service.
Run 'systemctl edit --user --force --full gnome-shell at x11.service' to
create a new unit.
porridge at debian:~$ systemctl --user edit gnome-shell at wayland.service
No files found for gnome-shell at wayland.service.
Run 'systemctl edit --user --force --full gnome-shell at wayland.service' to
create a new unit.

I wasn't sure whether it was OK to `--force`, or whether editing
gdm.service made sense without the other two. Please advise.

Marcin
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