Dear Maintainer,

I can’t log in with another user.
I see the lightdm screen, the login window.
I enter the login and its password (without AZERTY/QWERTY issue), and then
lghtdm is stuck.
I can’t even log in again, nor cancel anything, the login window is permanently
greyed. I have to kill lightdm by hand (thanks to lsof -Fp).

Yours,
nicolas

On 04/09/2024 10:58:13, Yves-Alexis Perez wrote:

Hi,

I think that there a truckload of lines in these logs.
How can I grep the right ones?

I can log in from su, and I opened a session with another user. Xnest and Xephyr are OK but without login manager.
The only thing that is not OK is logging in using the Change user button from xfce4-panel. This stucks lightdm after having entered the password.
I did not try from another login manager even if I also installed wdm (but it’s not wdm that comes with I try to change the user).

Yours,
nicolas patrois : pts noir asocial

Just get whatever lines happen when you encounter the problem, we'll narrow it
down later.

But can you *login* from the console?

Just to be sure what works and doesnt work here:

- login with 'user1' from lightdm
- logout from 'user1'
- login with 'user2' from lightdm
- logout from 'user2'
- login with 'user1' from lightdm
- *changing* from `user1` to `user2` from xfce [can you provide the exact
procedure you do here?]

Regards,

That looks spurious indeed (unless 'user2' login is actually '(null)')

So everything above *does* work?

So it's not the *login* (from a 'clean' lightdm with noone logged in) but
really the *change user* feature?


Regards,

[…]

I haven’t tried to log out because I still haven’t copied averything from the old machine.

Yes it is and this feature shows the usual lightdm login window.

Yours,
nicolas patrois : pts noir asocial

On 04/09/2024 11:25:39, Yves-Alexis Perez wrote:

I don’t have /var/log/syslog nor /var/log/auth.log my machine is rather young, I haven’t reinstalled everything).
In /var/log/lightdm/lightdm.log:

[+332255.25s] DEBUG: Greeter start authentication
[+332255.25s] DEBUG: Session pid=631863: Started with service 'lightdm', usernam
e '(null)'
[+332255.26s] DEBUG: Session pid=631863: Got 1 message(s) from PAM
[+332255.26s] DEBUG: Prompt greeter with 1 message(s)
[+332255.26s] WARNING: Session pid=631863: Invalid string length 1869348864 from child
[+332255.26s] DEBUG: Session pid=631863: Authentication complete with return value -1:

[+332255.26s] DEBUG: Authenticate result for user (null):

[+332255.26s] DEBUG: Session pid=631863: Exited with return value 1
[+332255.26s] DEBUG: Seat seat0: Session stopped
[+332255.76s] DEBUG: Greeter start authentication
[+332255.76s] DEBUG: Session pid=631864: Started with service 'lightdm', username '(null)'
[+332255.77s] DEBUG: Session pid=631864: Got 1 message(s) from PAM
[+332255.77s] DEBUG: Prompt greeter with 1 message(s)
[+332255.77s] WARNING: Session pid=631864: Invalid string length 1869348864 from child
[+332255.77s] DEBUG: Session pid=631864: Authentication complete with return value -1:

[+332255.77s] DEBUG: Authenticate result for user (null):

[+332255.77s] DEBUG: Session pid=631864: Exited with return value 1
[+332255.77s] DEBUG: Seat seat0: Session stopped
[+332255.96s] DEBUG: Greeter start authentication
[+332255.96s] DEBUG: Session pid=631865: Started with service 'lightdm', username '(null)'
[+332255.97s] DEBUG: Session pid=631865: Got 1 message(s) from PAM
[+332255.97s] DEBUG: Prompt greeter with 1 message(s)
[+332255.97s] WARNING: Session pid=631865: Invalid string length 1869348864 from child
[+332255.97s] DEBUG: Session pid=631865: Authentication complete with return value -1:

[+332255.97s] DEBUG: Authenticate result for user (null):
[+332255.97s] DEBUG: Session pid=631865: Exited with return value 1
[+332255.97s] DEBUG: Seat seat0: Session stopped
[+332256.59s] DEBUG: Greeter start authentication
[+332256.59s] DEBUG: Session pid=631866: Started with service 'lightdm', username '(null)'
[+332256.59s] DEBUG: Session pid=631866: Got 1 message(s) from PAM
[+332256.59s] DEBUG: Prompt greeter with 1 message(s)
[+332256.59s] WARNING: Session pid=631866: Invalid string length 1869348864 from child
[+332256.59s] DEBUG: Session pid=631866: Authentication complete with return value -1:

[+332256.59s] DEBUG: Authenticate result for user (null):

[+332256.60s] DEBUG: Session pid=631866: Exited with return value 1
[+332256.60s] DEBUG: Seat seat0: Session stopped
[+332258.90s] DEBUG: Seat seat0 changes active session to 2
[+332258.90s] DEBUG: Activating session 2
[+332268.92s] DEBUG: Process 631691 exited with return value 0
[+332268.92s] DEBUG: XServer 1: X server stopped
[+332268.92s] DEBUG: Releasing VT 8
[+332268.92s] DEBUG: XServer 1: Removing X server authority /var/run/lightdm/root/:1
[+332268.92s] DEBUG: Seat seat0: Display server stopped
[+332268.92s] DEBUG: Seat seat0: Stopping session
[+332268.92s] DEBUG: Terminating login1 session c7
[+332268.92s] DEBUG: Session pid=631731: Sending SIGTERM
[+332268.92s] DEBUG: Greeter closed communication channel
[+332268.92s] DEBUG: Session pid=631731: Exited with return value 1
[+332268.92s] DEBUG: Seat seat0: Session stopped
[+332268.92s] DEBUG: Seat seat0: Stopping display server, no sessions require it

- login with 'user1' from lightdm
[…]
- *changing* from `user1` to `user2` from xfce [can you provide the exact procedure you do here?]
Yep, and user3 instead of user2 also fails.
I click on the top right button in xfce4-panel, the one with user1’s name on it.
Then I choose the Change user menu entry, enter user2 (or user3) and his password in the login window, click on OK and boom.

Yours,
nicolas patrois : pts noir asocial

control: tag -1 unreproducible morinfo


Hi Nicolas,

I'm sorry you encounter that bug but could you provide some logs (from
/var/log/syslog, /var/log/auth.log, /var/log/lightdm/*...) of the various
attempts?

Can you login with those different users on the console? On another DM like
gdm3?

I don't experience this here so there's likely an issue on your end but it's a
bit hard to identify it like this.

Regards,

When you have a stable situation can you please retry and report back?

Ok.