SDDM does not unlock gnome-keyring on login

[Lastique]

On automatic login, SDDM does not unlock gnome-keyring, which suspends the boot process and asks for a password. The boot process blocks until the password is entered. Apparently, the boot process stops because Pidgin is in the autostart list and it requires access to the keyring.

The default keyring has a password that is the same as the password of the user that logs in automatically.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: sddm 0.17.0-1ubuntu7
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: KDE
Date: Sat May 5 20:08:59 2018
InstallationDate: Installed on 2015-05-01 (1099 days ago)
InstallationMedia: Kubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
SourcePackage: sddm
UpgradeStatus: Upgraded to bionic on 2018-05-05 (0 days ago)
mtime.conffile..etc.pam.d.sddm: 2018-05-05T20:03:52.840372
mtime.conffile..etc.pam.d.sddm-autologin: 2018-05-05T20:04:23.052211

[Lastique (andysem)]

Note that the attached modified pam.d/sddm and pam.d/sddm-autologin files are the result of my attempts to fix the problem. The problem exists with the original files.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Ang Bongsong (notinsideofhereiamnotinside)]

Can confirm that SDDM has trouble unlocking the default keyring. While it always seems to unlock it after a cold boot, at some point trouble arises when logging out and back in again, along with after resuming from suspend / hibernate. In those situations, the keyring remains locked far more often than not. I am experiencing this under Lubuntu 19.04. The issue has been occurring both before and after I migrated data over from an install of Ubuntu Xenial. I have not made changes to sddm configs, as the other user who filed this bug has.