Comment 78 for bug 1951491

IF that can help, I can reproduce the issue, with the snap working with a user and failing with another one.

Setup a fresh Ubuntu Server 22 in a VirtualBox hosted on Windows (but I also reproduce the issue on a dedicated server). No extra packages apart from an SSH server.

Once Ubuntu is available, run:

# Install Chromium
$ sudo snap install chromium
(...)

# Launch Chromium (okay, just print its version)
$ chromium --version
Chromium 108.0.5359.124 snap

# Create another user
$ sudo adduser otheruser
(...)

# Log as the new user
$ sudo su otheruser

# I expect Chromium to be available for this new user but...
$ chromium --version
/user.slice/user-1000.slice/session-3.scope is not a snap cgroup

In the last error message, 1000 is the id of the initial user, the first user who installed Chromium and who can run it. Not the id of otheruser, the new user who can’t run Chromium.

When running SNAPD_DEBUG=1 snap run chromium, with the initial user (success):

$ SNAPD_DEBUG=1 snap run chromium
2022/12/27 19:28:50.299534 tool_linux.go:204: DEBUG: restarting into "/snap/snapd/current/usr/bin/snap"
2022/12/27 19:28:50.317267 logger.go:184: DEBUG: -- snap startup {"stage":"start", "time":"1672169330.317265"}
2022/12/27 19:28:50.322615 cmd_run.go:1037: DEBUG: executing snap-confine from /snap/snapd/17883/usr/lib/snapd/snap-confine
2022/12/27 19:28:50.323853 cmd_run.go:440: DEBUG: SELinux not enabled
2022/12/27 19:28:50.324980 tracking.go:46: DEBUG: creating transient scope snap.chromium.chromium
2022/12/27 19:28:50.326309 tracking.go:186: DEBUG: using session bus
(...)

With otheruser (failure):

otherphil@ubuntu-22:/home/philippe$ SNAPD_DEBUG=1 snap run chromium
2022/12/27 19:27:01.059280 tool_linux.go:204: DEBUG: restarting into "/snap/snapd/current/usr/bin/snap"
2022/12/27 19:27:01.075310 logger.go:184: DEBUG: -- snap startup {"stage":"start", "time":"1672169221.075289"}
2022/12/27 19:27:01.082983 cmd_run.go:1037: DEBUG: executing snap-confine from /snap/snapd/17883/usr/lib/snapd/snap-confine
2022/12/27 19:27:01.083514 cmd_run.go:440: DEBUG: SELinux not enabled
2022/12/27 19:27:01.083753 tracking.go:46: DEBUG: creating transient scope snap.chromium.chromium
2022/12/27 19:27:01.083813 tracking.go:189: DEBUG: session bus is not available: cannot find session bus
2022/12/27 19:27:01.083818 cmd_run.go:1224: DEBUG: snapd cannot track the started application
2022/12/27 19:27:01.083822 cmd_run.go:1225: DEBUG: snap refreshes will not be postponed by this process
(...)

So the first diff is on "session bus is not available: cannot find session bus".