"Shell to examine situation" during upgrade fails

[Florian Bach]

I've just updated from Ubuntu 19.10 to Ubuntu 20.04 using the GUI updater (after it popped up and told me there was an update available).

It started downloading all the new updates, then when configuring the openssh-server, a new window popped up, telling me that the sshd_config has been changed in the package, and whether I want to take the maintainer's copy or keep my own one.

It gave me a couple of options, like keep maintainer one, keep my one, three-way diff, and "open a shell to examine the situation". I wanted to open a shell to take a look at both files - and then it froze. I selected that option, confirmed, and nothing happened, but I also couldn't cancel the process.

Looking at the output of pstree, the updater had started a nice new bash instance for me to examine the situation in - but I had no way of accessing that. The updater window didn't change, and no other new terminal window with that bash popped up, so the update was softlocked.

I had to manually find and kill that bash process to make the softlock go away (and then manually open a shell myself to look at the files), which wasn't that big of a deal for me, but will probably be fairly confusing for less experienced users.

I don't know if I made some mistake that made that error happen, but then again there aren't that many things to do wrong performing an update, right?

Unfortunately, I've now already updated to 20.04 so I can't include the version of the update tool I had in 19.10 since that will probably have changed by now. Currently, on 20.04, I have ubuntu-release-upgrader-core and -gtk 1:20.04.19.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.19
ProcVersionSignature: Ubuntu 5.4.0-29.33-generic 5.4.30
Uname: Linux 5.4.0-29-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sun May 10 10:14:10 2020
InstallationDate: Installed on 2019-08-17 (267 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2020-05-09 (0 days ago)
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

This might have something to do with what went wrong:

Setting up openssh-client (1:8.2p1-4) ...
Installing new version of config file /etc/ssh/ssh_config ...
Setting up libc6-dev:amd64 (2.31-0ubuntu9) ...
Setting up openssh-sftp-server (1:8.2p1-4) ...
Setting up openssh-server (1:8.2p1-4) ...
Installing new version of config file /etc/ssh/moduli ...
]0;root@florian-desktop: /root@florian-desktop:/# /usr/bin/ucf: Zeile 1008: 4453 Getötet bash > /dev/tty < /dev/tty
rescue-ssh.target is a disabled or a static unit, not starting it.

[Florian Bach (leseratte10)]

That was me manually killing the bash process since it was softlocked.

[Launchpad Janitor (janitor)]

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