Arch Linux

CharlieBra7o

Member

Registered: 2014-03-01

Posts: 23

systemctl --user: Failed to connect to user scope bus via local tra...

systemd 257.1-1

I am starting to get the following error when running `systemctl --user` commands (any) on one of my headless machines a few seconds/minutes after boot:

❯ systemctl --user daemon-reload
Failed to connect to user scope bus via local transport: Connection refused

This means that I can boot the system, login via SSH and then run some `systemctl --user` command(s) and then after a few seconds or minutes (non-deterministic) I will start to get this error. The system will never recover from this.

Another one of my machines is almost identical but doesn't have this issue. Both systems have the following environment variables:

❯ echo $XDG_RUNTIME_DIR
/run/user/1000

❯ echo $DBUS_SESSION_BUS_ADDRESS
unix:path=/run/user/1000/bus

Other than that I checked if any critical systemd service failed but no. I cannot see anything suspicious in the journal.

Since I cannot find this exact error message anywhere on the internet I really hope someone has a hint for me!

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 8,738

Website

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I cannot see anything suspicious in the journal

Probably best to share it here then. Somebody might spot something you've missed.

---

Para todos todo, para nosotros nada

-thc

Member

Registered: 2017-03-15

Posts: 775

Re: systemctl --user: Failed to connect to user scope bus via local tra...

Wild guess: AppArmor environment variable scrubbing?

CharlieBra7o

Member

Registered: 2014-03-01

Posts: 23

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I did some more testing now and found out that

- NeoVIM is the issue!
- BOTH my machines have this issue

I can reproduce this as follows:

1. Boot
2. Now systemctl --user commands work fine ... until:
3. The moment I open any ~/.config/systemd/user/*.service file using NeoVIM (other editors do not cause any issues, including regular VIM)

These do not show any messages (not even debug) when the issue occurs:

systemctl -t systemd[
systemctl --user -t systemd

I will do some further testing using
- older NeoVIM versions
- NeoVIM without config/plugins

Maybe there is some file lock from a git plugin or whatever

Last edited by CharlieBra7o (2025-01-14 09:53:04)

Salkay

Member

Registered: 2014-05-22

Posts: 650

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I've also been bitten by this same regression. I actually get this with regular VIM, editing from the TTY. I do have the gvim version installed though, which is compiled with a few more options than vanilla vim. FWIW I also tested nano, and this doesn't trigger the bug.

bretello

Member

Registered: 2025-01-15

Posts: 2

Re: systemctl --user: Failed to connect to user scope bus via local tra...

What triggers this is running the following command:

systemd-analyze --user verify ~/.local/share/systemd/user/<unit>.service

which many linters use for systemd unit files

Salkay

Member

Registered: 2014-05-22

Posts: 650

Re: systemctl --user: Failed to connect to user scope bus via local tra...

Thanks @bretello. I can confirm that this also breaks systemd --user for me. A reboot is necessary to fix it.

CharlieBra7o

Member

Registered: 2014-03-01

Posts: 23

Re: systemctl --user: Failed to connect to user scope bus via local tra...

What triggers this is running the following command:

systemd-analyze --user verify ~/.local/share/systemd/user/<unit>.service

which many linters use for systemd unit files

Interesting! Thanks for this insight.

Does this mean that the command systemd-analyze has a bug and it is triggered by one of my NeoVIM plugins?

bretello

Member

Registered: 2025-01-15

Posts: 2

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I was able to reproduce even without calling `systemd-analyze --user`, so there's something else going on, smells like a pretty bad regression in systemd.

jeremija

Member

Registered: 2016-10-09

Posts: 10

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I seem to be getting the same thing in sway (using sddm) and when trying to log in to the TTY directly.

Funny thing, I ran an upgrade, and the `systemctl --user` commands started working at some point during the upgrade, and they stopped working after the upgrade had completed. Something weird is going on.

Update: when I disable sddm and reboot, and then login from TTY things start to work again.

Last edited by jeremija (2025-01-19 11:52:14)

farben.rausch

Member

Registered: 2011-10-25

Posts: 21

Re: systemctl --user: Failed to connect to user scope bus via local tra...

I have a related issue, didn't find the problem yet tough

cookiecaper

Member

Registered: 2007-09-22

Posts: 199

Re: systemctl --user: Failed to connect to user scope bus via local tra...

So I just came across something interesting when working on this problem. If I unset XDG_RUNTIME_DIR, systemctl --user works.

[jeff@kvm-master ~]$ printenv XDG_RUNTIME_DIR
/run/user/1000
[jeff@kvm-master ~]$ systemctl --user
Failed to connect to user scope bus via local transport: Connection refused
[jeff@kvm-master ~]$ unset XDG_RUNTIME_DIR
[jeff@kvm-master ~]$ systemctl --user
  UNIT                                                                                                                     LOAD      ACTIVE SUB       DESCRIPTION

It seems that systemd can successfully infer the XDG_RUNTIME_DIR if it's not in the environment. I wonder if something gets funky with the /run/user/1000 directory. Will continue troubleshooting, but thought I should report this finding.

Quick edit: running

systemctl --user daemon-reexec

from a session without XDG_RUNTIME_DIR set seems to fix it for sessions that do have XDG_RUNTIME_DIR set. Much better than a hard reboot!

Last edited by cookiecaper (2025-01-29 04:26:50)

RetroZelda

Member

Registered: 2025-02-01

Posts: 1

Re: systemctl --user: Failed to connect to user scope bus via local tra...

ran into this today as well.  Although im on debian testing, this thread is what google provided me so ill share what I found and what my fix was.  It might help arch users, and it might help other lost debian souls.

when I checked what was in my XDG_RUNTIME_DIR

$ printenv XDG_RUNTIME_DIR
/run/user/1000

I noticed that it did not match the permissions set in here:

$ ls -al /run/user/
total 0
drwxr-xr-x  4 root       root        80 Jan 31 22:58 .
drwxr-xr-x 29 root       root       840 Jan 31 22:58 ..
drwx------  4 firstuser  firstuser  120 Jan 31 22:58 1000
drwx------  4 targetuser targetuser 120 Jan 31 22:55 1001

since the permission of the dir set in XDG_RUNTIME_DIR was for the wrong user, I just run this to fix it

export XDG_RUNTIME_DIR=/run/user/1001

Last edited by RetroZelda (2025-02-01 04:19:21)

Salkay

Member

Registered: 2014-05-22

Posts: 650

Re: systemctl --user: Failed to connect to user scope bus via local tra...

Thanks for posting @RetroZelda. Much appreciated. Sorry, are you saying that your logged in user is targetuser?

FWIW when I run your commands, /run/user/1000 (i.e. /run/user/1000) is indeed owned by my logged in user.