Bug#1118454: gdm3: GDM3 49 fails startup with: unix_chkpwd[2062]: could not obtain user info (gdm-greeter)

[Alessandro Astone]

On 20/10/2025 14:10, Frederik Himpe wrote:
> Package: gdm3
> Version: 49.1-1
> Severity: important
> X-Debbugs-Cc: frederik at frehi.be
> 
> Dear Maintainer,
> 
> I upgraded to gdm 49.1 from Experimental, and now GDM3 fails to start: it just
> hangs.
> 
> In the logs I found this error:
> unix_chkpwd[2062]: could not obtain user info (gdm-greeter)
> 
> I found this similar bug:
> https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2121017
> 
> I do have libnss-systemd 258.1-1 installed and /etc/nsswitch.conf contains
> passwd:         files systemd
> group:          files systemd

There was also an AppArmor profile preventing access to the new gdm 
userdb service.
See bug https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2119541 
and the fix https://gitlab.com/apparmor/apparmor/-/merge_requests/1761 
which you can apply to your local 
/etc/apparmor.d/abstractions/nss-systemd file