gdm broken after update

seth · 2025-09-23 15:45:17

homed is pure spam, you can ignore that.
https://wiki.archlinux.org/title/Systemd-homed

Sep 23 16:05:39 pc gnome-session-i[1184]: Failed to start unit gnome-session-x11@gnome-login.target: GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit gnome-session-x11@gnome-login.target not found.

GDM on X11 currently does not work - if you've https://wiki.archlinux.org/title/GDM#Use_Xorg_backend you'll have to disable that and/or try https://bbs.archlinux.org/viewtopic.php … 8#p2263248

If there're wayland related errors ahead of that we'd need to see those.

lpr1 · 2025-09-23 15:48:36

Hanabishi wrote:

But actually read the response from the package maintainer:
I'm resistant to reënabling it. It will get removed entirely next cycle. If you need an X11 session, don't use GNOME.

Good that GNOME developers think that way, after 12+ years of using GNOME, I finally removed it yesterday. Wayland is nowhere near usable, it tries to solve the problem that doesn't exist, the arrogance of some developers is beyond acceptable, there's a reason why X11 works the way it does, there is a reason why even Windows have tearing "issues", and that reason is latency. Wayland have unacceptable latency, and no matter what voodoo magic words you use, fact remains, if you don't have tearing with static refresh rates, you have a latency issues, it really is that simple. This is by far the worst decision GNOME developers/management did, to be so arrogant and feeding on your own delusions, means that you, at the same time, think higher of yourself than those who did work on X11, while in reality, it's unlikely those developers are even at the same level of knowledge..., this really is the next level of arrogance and believeing your own delusions...

Unfortunatelly, there's no DE that fills the gap properly for the needs of the users like me, most of them are extremely buggy, or unconvinient, heavy, in your way..., Budgie seems the only option that is semi-acceptable (still buggy as f.). Had to vent it out, sorry.

FuzzySPb · 2025-09-23 15:55:19

seth wrote:

GDM on X11 currently does not work - if you've https://wiki.archlinux.org/title/GDM#Use_Xorg_backend you'll have to disable that and/or try https://bbs.archlinux.org/viewtopic.php … 8#p2263248

Ooh... Yep, it fixed my problem. THANK YOU. But interesting that it failed only today...

seth · 2025-09-23 16:05:08

@lpr1, I understand and share your frustration but please try to stay on topic, the thread on this clusterbug is noisy enough
@FuzzySPb
\o/
So at least this is sorted out. Ftr, did you symlink xsessions or simply switch to wayland?

Back to the PAM problem:
So unix_chkpwd checks /etc/shadow and is typically called from the unix pam module.

sudo grep -i gdm /etc/shadow

will likely yield no results.
If anybody has downgraded gnome to deal w/ this: do you have a shadow entry for gdm?
Also there're probably some /etc/pam.d/*gdm* ?

GDM should™ not use pam_unix/shadow when there's no shadow entry, but what if you just add

gdm-greeter:!*:20224::::::

to /etc/shadow?

FuzzySPb · 2025-09-23 16:15:40

seth wrote:

Ftr, did you symlink xsessions or simply switch to wayland?

I commented line "WaylandEnable=false" in /etc/gdm/custom.conf

ReLoneR · 2025-09-23 16:29:22

seth wrote:

/or try https://bbs.archlinux.org/viewtopic.php … 8#p2263248

i did not switch to wayland and tried only symlinking.
There were not any errors but i just got a black screen, did not reach a gnome desktop

seth · 2025-09-23 16:35:55

@Reloner, but you can start GDM itself? Your problem atm is "only" to start a gnome/X11 session?

Everyone else:
Why is there even a gdm-greeter user?

grep -r greeter /etc/passwd /usr/lib/sysusers.d

stesind · 2025-09-23 16:36:43

"GDM should™ not use pam_unix/shadow when there's no shadow entry, but what if you just add

gdm-greeter:!*:20224::::::

to /etc/shadow?"

This seems to do the trick. Now I see GDM and can login after updating from core-testing and extras-testing.. I don't know if something else was updated in the last 8 hours because I rolled back to gnome 48.5

lpr1 · 2025-09-23 16:38:09

seth wrote:

@lpr1, I understand and share your frustration but please try to stay on topic, the thread on this clusterbug is noisy enough

Alrigh, sorry, I have nothing to contribute to the topic sadly, aside from the well known fact that login with X11 fails.

ybon · 2025-09-23 16:40:25

I'm in the same situation.

Here is my journalctl -b: https://0x0.st/KARE.txt

I've already "# WaylandEnable=false" in /etc/gdm/custom.conf.

Here is my output of "sudo grep -i gdm /etc/shadow":

gdm:!:16892:0:99999:7:::

"grep -r greeter /etc/passwd /usr/lib/sysusers.d" does not output anything for me.

One thing to add: even the TTYs seem to freeze very often, so I need to restart a bunch of times before I can get a terminal session through TTY and then manually run "gnome-shell --wayland".

Last edited by ybon (2025-09-23 16:43:29)

stopka · 2025-09-23 16:58:03

adding the gdm-greeter user to /etc/shadow worked. GDM started, and I succesfully logged in to gnome 49 on wayland.

gdm-greeter:!*:20224::::::

why the user is not needed on other machines I have?

Last edited by stopka (2025-09-23 17:34:15)

ReLoneR · 2025-09-23 17:10:01

seth wrote:

@Reloner, but you can start GDM itself? Your problem atm is "only" to start a gnome/X11 session?

with autologin enabled - there were no errors on boot, and black screen after that
with autologin disabled - there were no errors on boot, and an infinite cycle of black screen->blinking cursor->black screen...

ybon · 2025-09-23 17:12:33

adding the gdm-greeter user to /etc/passwd worked. GDM started, and I succesfully logged in to gnome 49 on wayland.

Worked for me too (on /etc/shadow)!

mypetbirdrules · 2025-09-23 17:33:28

I have had the same Arch Linux installation since the mid-2010s, though it has moved between different iterations of Thinkpad laptops over the years. Upon updating to GNOME 49, I ran into the same issue as other users in this thread. If you are like me and:

1. Use Wayland
2. Use GDM with GNOME
3. Suddenly ran into an issue where booting was met with a black screen and either a blinking or solid white underline at the top left

Then we might have had the same issue.

I had the following log messages:

journalctl -r

Sep 23 13:11:00 USERNAME systemd[1]: Failed to start User Manager for UID 60588.
Sep 23 13:11:00 USERNAME systemd[1]: user@60588.service: Failed with result 'exit-code'.
Sep 23 13:11:00 USERNAME systemd[1]: user@60588.service: Main process exited, code=exited, status=224/PAM
Sep 23 13:11:00 USERNAME (systemd)[1114]: user@60588.service: Failed at step PAM spawning /usr/lib/systemd/systemd: Operation not permitted
Sep 23 13:11:00 USERNAME (systemd)[1114]: user@60588.service: Failed to set up PAM session: Operation not permitted
Sep 23 13:11:00 USERNAME (systemd)[1114]: user@60588.service: PAM failed: Authentication service cannot retrieve authentication info

If this applies to you, then what fixed it for me was appending the following to my /etc/shadow file:

gdm-greeter:!*:20224::::::

Note: I did not have to rollback the versions of any software package. This solves the GDM permission issue on Wayland with the latest package versions available. Thank you to everyone in the thread who helped troubleshoot this!

calculon102 · 2025-09-23 17:34:09

ybon wrote:

adding the gdm-greeter user to /etc/passwd worked. GDM started, and I succesfully logged in to gnome 49 on wayland.
Worked for me too (on /etc/shadow)!

I confirm this. Worked for me, too.

Edit:
Also, thanks a lot. Especially Seth for your moderation!

Now I wonder, what the root cause is.

Last edited by calculon102 (2025-09-23 17:37:08)

weaseal · 2025-09-23 17:35:34

Can anyone explain simple steps to get X11 working again? I play some old games from the 90s and they don't work well in Wayland. I'd like to get X11 enabled again.

calculon102 · 2025-09-23 18:17:41

weaseal wrote:

Can anyone explain simple steps to get X11 working again? I play some old games from the 90s and they don't work well in Wayland. I'd like to get X11 enabled again.

In my understanding, for the other users one of these seemed to work:

1. Repair missing element in filesystem.

sudo ln -s /usr/share/wayland-sessions/ /usr/share/xsessions

2. Force X11 for GDM. Edit /etc/gdm/custom.conf as root and uncomment the line / insert

WaylandEnable=false

bboozzoo · 2025-09-23 18:35:47

calculon102 wrote:

ybon wrote:
adding the gdm-greeter user to /etc/passwd worked. GDM started, and I succesfully logged in to gnome 49 on wayland.
Worked for me too (on /etc/shadow)!
I confirm this. Worked for me, too.
Edit:
Also, thanks a lot. Especially Seth for your moderation!
Now I wonder, what the root cause is.

but how the hell did this package get out from testing if it's clear it should be adding the user in postinst snippet or something like that? Has it been magically working for all those users who have the testing repos enabled in their systems?

weaseal · 2025-09-23 18:51:18

calculon102 wrote:

In my understanding, for the other users one of these seemed to work:
1. Repair missing element in filesystem.
sudo ln -s /usr/share/wayland-sessions/ /usr/share/xsessions
2. Force X11 for GDM. Edit /etc/gdm/custom.conf as root and uncomment the line / insert
WaylandEnable=false

Unfortunately gdm won't start at all after the 2nd step, had to undo that change

dcc24 · 2025-09-23 19:16:00

seth wrote:

Back to the PAM problem:
So unix_chkpwd checks /etc/shadow and is typically called from the unix pam module.
sudo grep -i gdm /etc/shadow
will likely yield no results.
If anybody has downgraded gnome to deal w/ this: do you have a shadow entry for gdm?
Also there're probably some /etc/pam.d/*gdm* ?

I have downgraded the whole Gnome stack to the previous 48.x packages and I have this:

$ sudo grep -i gdm /etc/shadow
gdm:!:18151::::::
$ sudo ls -al /etc/pam.d/ | grep gdm
-rw-r--r--   1 root root   572 Jun  4 21:15 gdm-autologin
-rw-r--r--   1 root root   694 Jun  4 21:15 gdm-fingerprint
-rw-r--r--   1 root root   896 Jun  4 21:15 gdm-launch-environment
-rw-r--r--   1 root root   449 Jun  4 21:15 gdm-password
-rw-r--r--   1 root root   724 Jun  4 21:15 gdm-smartcard

mypetbirdrules wrote:

I have had the same Arch Linux installation since the mid-2010s, though it has moved between different iterations of Thinkpad laptops over the years. Upon updating to GNOME 49, I ran into the same issue as other users in this thread. If you are like me and:
1. Use Wayland
2. Use GDM with GNOME
3. Suddenly ran into an issue where booting was met with a black screen and either a blinking or solid white underline at the top left
Then we might have had the same issue.

All of these apply to me too, including a very old install:

$ sudo head -1 /var/log/pacman.log
[2013-10-21 22:20] [PACMAN] Running 'pacman -r /mnt -Sy --cachedir=/mnt/var/cache/pacman/pkg base'

mypetbirdrules wrote:

If this applies to you, then what fixed it for me was appending the following to my /etc/shadow file:
gdm-greeter:!*:20224::::::
Note: I did not have to rollback the versions of any software package. This solves the GDM permission issue on Wayland with the latest package versions available. Thank you to everyone in the thread who helped troubleshoot this!

This is very encouraging, thanks! Maybe I should just bite the bullet, upgrade again, and try this.

seth · 2025-09-23 19:18:15

@weaseal, this will first and foremost allow you (if so) to run GDM on X11, afaiu gnome one X11 is already no longer supported and even iff, it's on the chopping block for sure.
If you intend to run X11 for some future, you'll have to consider a different DE

@ReLoneR
We'll need to see a journal for that and what's going on there.
Will also be interesting for weaseal
Can you run GDM/Gnome on wayland t hen?

@Everyone

but how the hell did this package get out from testing

Now I wonder, what the root cause is.

why the user is not needed on other machines I have?

It seems that not every system is affected so this might not have flared up in the testing repos, esp. if this hinges on some stale configs (anyone here w/ a rather recent first gnome installation ever?)
If you've access to an unaffected system, please
1. check its /etc/shadow and see whether any GDM users show up there
2. check/post a journal from that system to see whether some gdm-greeter user shows up there at all, you can also check "id gdm-greeter"

dcc24 · 2025-09-23 19:23:31

seth wrote:

It seems that not every system is affected so this might not have flared up in the testing repos, esp. if this hinges on some stale configs (anyone here w/ a rather recent first gnome installation ever?)
If you've access to an unaffected system, please
1. check its /etc/shadow and see whether any GDM users show up there
2. check/post a journal from that system to see whether some gdm-greeter user shows up there at all, you can also check "id gdm-greeter"

Here's some data from a recent (April 2025) Arch install where I don't have this problem:

$ sudo id gdm-greeter
id: ‘gdm-greeter’: no such user
$ sudo grep -i gdm /etc/shadow
gdm:!*:20180::::::
$ sudo ls -al /etc/pam.d | grep gdm
-rw-r--r--  1 root root  572 Sep 16 19:53 gdm-autologin
-rw-r--r--  1 root root  694 Sep 16 19:53 gdm-fingerprint
-rw-r--r--  1 root root  911 Sep 16 19:53 gdm-launch-environment
-rw-r--r--  1 root root  449 Sep 16 19:53 gdm-password
-rw-r--r--  1 root root  724 Sep 16 19:53 gdm-smartcard
$ pacman -Q gdm systemd gnome-shell mutter gjs
gdm 49.0.1-1
systemd 258-2
gnome-shell 1:49.0-1
mutter 49.0-3
gjs 2:1.86.0-1

EDIT: Here are some journal entries as well:

Sep 23 20:19:26 x1 systemd-logind[662]: New session '1' of user 'gdm-greeter' with class 'greeter' and type 'wayland'.
Sep 23 20:19:26 x1 systemd[1]: Created slice User Slice of UID 60578.

Sep 23 20:19:26 x1 systemd[1]: Starting User Runtime Directory /run/user/60578...
Sep 23 20:19:26 x1 systemd[1]: proc-sys-fs-binfmt_misc.automount: Got automount request for /proc/sys/fs/binfmt_misc, triggered by 986 (tailscaled)
Sep 23 20:19:26 x1 systemd[1]: Mounting Arbitrary Executable File Formats File System...
Sep 23 20:19:26 x1 systemd[1]: Finished User Runtime Directory /run/user/60578.
Sep 23 20:19:26 x1 systemd[1]: Starting User Manager for UID 60578...
Sep 23 20:19:26 x1 systemd[1]: Mounted Arbitrary Executable File Formats File System.

Sep 23 20:19:26 x1 (systemd)[995]: pam_warn(systemd-user:setcred): function=[pam_sm_setcred] flags=0x8002 service=[systemd-user] terminal=[/dev/tty1] user=[gdm-greeter] ruser=[<unknown>] rhos
t=[<unknown>]
Sep 23 20:19:26 x1 (systemd)[995]: pam_unix(systemd-user:session): session opened for user gdm-greeter(uid=60578) by gdm-greeter(uid=0)

Sep 23 20:19:26 x1 systemd-logind[662]: New session '2' of user 'gdm-greeter' with class 'manager-early' and type 'unspecified'.                                                               

Sep 23 20:19:26 x1 gnome-session-i[1170]: Starting GNOME session target: gnome-session-wayland@gnome-login.target
Sep 23 20:19:26 x1 systemd[995]: Created slice Slice /app/gnome-session-manager.
Sep 23 20:19:26 x1 systemd[995]: Reached target GNOME Wayland Session.
Sep 23 20:19:26 x1 systemd[995]: Reached target Session services which should run early before the graphical session is brought up.
Sep 23 20:19:26 x1 systemd[995]: Reached target GNOME Shell.
Sep 23 20:19:26 x1 systemd[995]: Starting Monitor Session leader for GNOME Session...
Sep 23 20:19:27 x1 systemd[995]: Started Monitor Session leader for GNOME Session.
Sep 23 20:19:27 x1 systemd[995]: Reached target Tasks to be run before GNOME Session starts.
Sep 23 20:19:27 x1 systemd[995]: Starting GNOME Session Manager (session: gnome-login)...
Sep 23 20:19:27 x1 systemd[995]: Started GNOME Session Manager (session: gnome-login).
Sep 23 20:19:27 x1 systemd[995]: Reached target GNOME Session Manager is ready.
Sep 23 20:19:27 x1 systemd[995]: Starting GNOME Shell on Wayland...
Sep 23 20:19:27 x1 gnome-shell[1186]: Running GNOME Shell (using mutter 49.0) as a Wayland display server

Last edited by dcc24 (2025-09-23 19:58:04)

seth · 2025-09-23 19:58:36

So the gdm-greeter shows up and causes a warning

Sep 23 20:19:26 x1 (systemd)[995]: pam_warn(systemd-user:setcred): function=[pam_sm_setcred] flags=0x8002 service=[systemd-user] terminal=[/dev/tty1] user=[gdm-greeter] ruser=[<unknown>] rhost=[<unknown>]

but then sails through

Sep 23 20:19:26 x1 (systemd)[995]: pam_unix(systemd-user:session): session opened for user gdm-greeter(uid=60578) by gdm-greeter(uid=0)

despite not being in /etc/shadow…

It might help to diff

md5sum /{etc,usr/lib}/pam.d/*

between the systems.

windy · 2025-09-23 19:59:17

So here is my journal as promised: https://0x0.st/Kms_.txt

The most interesting part from my point of view:

gnome-session-i[1132]: Starting GNOME session target: gnome-session-x11@gnome-login.target
gnome-session-i[1132]: Failed to start unit gnome-session-x11@gnome-login.target: GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit gnome-session-x11@gnome-login.target not found.
kernel: traps: gnome-session-i[1132] trap int3 ip:7f99bb0b5b8c sp:7ffd272ead90 error:0 in libglib-2.0.so.0.8600.0[64b8c,7f99bb06f000+a7000]
systemd-coredump[1140]: Process 1132 (gnome-session-i) of user 60578 terminated abnormally with signal 5/TRAP, processing...
systemd[1]: Created slice Slice /system/systemd-coredump.
systemd[1]: Started Process Core Dump (PID 1140/UID 0).
systemd-coredump[1141]: Process 1132 (gnome-session-i) of user 60578 dumped core.

                                             Stack trace of thread 1132:
                                             #0  0x00007f99bb0b5b8c g_log_structured_array (libglib-2.0.so.0 + 0x64b8c)
                                             #1  0x00007f99bb0b62e0 g_log_default_handler (libglib-2.0.so.0 + 0x652e0)
                                             #2  0x00007f99bb0b657a g_logv (libglib-2.0.so.0 + 0x6557a)
                                             #3  0x00007f99bb0b6904 g_log (libglib-2.0.so.0 + 0x65904)
                                             #4  0x0000560b34f52686 n/a (/usr/lib/gnome-session-init-worker + 0x2686)
                                             #5  0x00007f99bae27675 n/a (libc.so.6 + 0x27675)
                                             #6  0x00007f99bae27729 __libc_start_main (libc.so.6 + 0x27729)
                                             #7  0x0000560b34f52c95 n/a (/usr/lib/gnome-session-init-worker + 0x2c95)

                                             Stack trace of thread 1137:
                                             #0  0x00007f99baf1876d syscall (libc.so.6 + 0x11876d)
                                             #1  0x00007f99bb0e07ee g_cond_wait (libglib-2.0.so.0 + 0x8f7ee)
                                             #2  0x00007f99bb0771cd n/a (libglib-2.0.so.0 + 0x261cd)
                                             #3  0x00007f99bb0e9447 n/a (libglib-2.0.so.0 + 0x98447)
                                             #4  0x00007f99bb0e887c n/a (libglib-2.0.so.0 + 0x9787c)
                                             #5  0x00007f99bae969cb n/a (libc.so.6 + 0x969cb)
                                             #6  0x00007f99baf1aa0c n/a (libc.so.6 + 0x11aa0c)

                                             Stack trace of thread 1139:
                                             #0  0x00007f99bae9f042 n/a (libc.so.6 + 0x9f042)
                                             #1  0x00007f99bae931ac n/a (libc.so.6 + 0x931ac)
                                             #2  0x00007f99bae931f4 n/a (libc.so.6 + 0x931f4)
                                             #3  0x00007f99baf0da36 ppoll (libc.so.6 + 0x10da36)
                                             #4  0x00007f99bb0b1744 n/a (libglib-2.0.so.0 + 0x60744)
                                             #5  0x00007f99bb0b19d7 g_main_loop_run (libglib-2.0.so.0 + 0x609d7)
                                             #6  0x00007f99bb322264 n/a (libgio-2.0.so.0 + 0x11a264)
                                             #7  0x00007f99bb0e887c n/a (libglib-2.0.so.0 + 0x9787c)
                                             #8  0x00007f99bae969cb n/a (libc.so.6 + 0x969cb)
                                             #9  0x00007f99baf1aa0c n/a (libc.so.6 + 0x11aa0c)

                                             Stack trace of thread 1138:
                                             #0  0x00007f99bae9f042 n/a (libc.so.6 + 0x9f042)
                                             #1  0x00007f99bae931ac n/a (libc.so.6 + 0x931ac)
                                             #2  0x00007f99bae931f4 n/a (libc.so.6 + 0x931f4)
                                             #3  0x00007f99baf0da36 ppoll (libc.so.6 + 0x10da36)
                                             #4  0x00007f99bb0b1744 n/a (libglib-2.0.so.0 + 0x60744)
                                             #5  0x00007f99bb0b1825 g_main_context_iteration (libglib-2.0.so.0 + 0x60825)
                                             #6  0x00007f99bb0b1872 n/a (libglib-2.0.so.0 + 0x60872)
                                             #7  0x00007f99bb0e887c n/a (libglib-2.0.so.0 + 0x9787c)
                                             #8  0x00007f99bae969cb n/a (libc.so.6 + 0x969cb)
                                             #9  0x00007f99baf1aa0c n/a (libc.so.6 + 0x11aa0c)
                                             ELF object binary architecture: AMD x86-64

I do not see any PAM errors
No "Process org.freedesktop.systemd1 exited with status 1"
/usr/share/xsessions is populated with entries from Cinnamon
WaylandEnable=false was already set
lightdm works

stronnag · 2025-09-23 20:04:40

Well, well it all works again on the two 10+ years old machines with latest:

* systemd 258-3
* gnome-shell 49.0-2
* adding gdm-greeter to /etc/shadow

The worst behaved machine had an ancient /var/lib/AccountsService/users/gdm with `XSession=` (vice `XSession=gnome-wayland`), probably a 10+ year old artefact that didn't help.

Why the addition of gdm-greeter to /etc/shadow is only need on older machines is a mystery to me; perhaps some other ancient artefact.

Arch Linux

#51 2025-09-23 15:45:17

Re: gdm broken after update

#52 2025-09-23 15:48:36

Re: gdm broken after update

#53 2025-09-23 15:55:19

Re: gdm broken after update

#54 2025-09-23 16:05:08

Re: gdm broken after update

#55 2025-09-23 16:15:40

Re: gdm broken after update

#56 2025-09-23 16:29:22

Re: gdm broken after update

#57 2025-09-23 16:35:55

Re: gdm broken after update

#58 2025-09-23 16:36:43

Re: gdm broken after update

#59 2025-09-23 16:38:09

Re: gdm broken after update

#60 2025-09-23 16:40:25

Re: gdm broken after update

#61 2025-09-23 16:58:03

Re: gdm broken after update

#62 2025-09-23 17:10:01

Re: gdm broken after update

#63 2025-09-23 17:12:33

Re: gdm broken after update

#64 2025-09-23 17:33:28

Re: gdm broken after update

#65 2025-09-23 17:34:09

Re: gdm broken after update

#66 2025-09-23 17:35:34

Re: gdm broken after update

#67 2025-09-23 18:17:41

Re: gdm broken after update

#68 2025-09-23 18:35:47

Re: gdm broken after update

#69 2025-09-23 18:51:18

Re: gdm broken after update

#70 2025-09-23 19:16:00

Re: gdm broken after update

#71 2025-09-23 19:18:15

Re: gdm broken after update

#72 2025-09-23 19:23:31

Re: gdm broken after update

#73 2025-09-23 19:58:36

Re: gdm broken after update

#74 2025-09-23 19:59:17

Re: gdm broken after update

#75 2025-09-23 20:04:40

Re: gdm broken after update

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