do-release-upgrade freezes

[uranium]

I'm trying to upgrade from Bionic to Fossa; I've had several problems with do-release-upgrade that may all stem from the same issue.

I run "sudo update-manager" at the command line.

The system alerts me of a potential upgrade: "The software on this computer is up to date. However, Ubuntu 20.04.1 LTS is now available (you have 18.04)."

I click "Upgrade..."

I pops up the release notes window, but never populates it; it stays empty, but otherwise correctly drawn, offering "Cancel" and "Upgrade".

In the command-line window is:

----------------------------------------
uranium@Hex:~$ sudo update-manager
[sudo] password for uranium:
Checking for a new Ubuntu release
/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcher.py:23: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk, Gdk
/usr/lib/python3/dist-packages/DistUpgrade/ReleaseNotesViewerWebkit.py:33: PyGIWarning: WebKit2 was imported without specifying a version first. Use gi.require_version('WebKit2', '4.0') before import to ensure that the right version gets loaded.
  from gi.repository import WebKit2 as WebKit
Gtk-Message: 09:10:22.336: GtkDialog mapped without a transient parent. This is discouraged.
----------------------------------------

If I accept the upgrade anyway, despite that, it pops up another window that appears to run do-release-upgrade and say it's downloading something, before vanishing and being replace by one with the title "Distribution Upgrade". That one doesn't draw properly--other than the title bar, it's blank, and just grabs whatever's behind it, or whatever was on a different desktop if I flip back and forth. On the command line is:

----------------------------------------
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'
----------------------------------------

It never gets any further. If I click the close box, it hangs. Eventually Metacity offers to kill it, which I accept. Nothing happens in the command line when I do. Eventually I control-C it, and get this:

^CTraceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-mv88pmez/focal", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-mv88pmez/DistUpgrade/DistUpgradeMain.py", line 235, in main
    save_system_state(logdir)
  File "/tmp/ubuntu-release-upgrader-mv88pmez/DistUpgrade/DistUpgradeMain.py", line 134, in save_system_state
    universal_newlines=True).communicate()[0]
  File "/usr/lib/python3.6/subprocess.py", line 850, in communicate
    stdout = self.stdout.read()
KeyboardInterrupt

If instead I try to initiate the upgrade myself with do-release-upgrade, I get this:

----------------------------------------
uranium@Hex:~$ sudo do-release-upgrade --allow-third-party
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1,554 B]
Get:2 Upgrade tool [1,336 kB]
Fetched 1,338 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'

Reading cache
----------------------------------------

And then it never gets any further.
Ctrl-c gives me this:

----------------------------------------
^C
Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-0gokn788/focal", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-0gokn788/DistUpgrade/DistUpgradeMain.py", line 235, in main
    save_system_state(logdir)
  File "/tmp/ubuntu-release-upgrader-0gokn788/DistUpgrade/DistUpgradeMain.py", line 134, in save_system_state
    universal_newlines=True).communicate()[0]
  File "/usr/lib/python3.6/subprocess.py", line 850, in communicate
    stdout = self.stdout.read()
KeyboardInterrupt
----------------------------------------

More info:

uranium@Hex:~$ lsb_release -rd
Description: Ubuntu 18.04.5 LTS
Release: 18.04
uranium@Hex:~$ apt-cache policy update-manager
update-manager:
  Installed: 1:18.04.11.13
  Candidate: 1:18.04.11.13
  Version table:
 *** 1:18.04.11.13 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
        100 /var/lib/dpkg/status
     1:18.04.11 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu bionic/main i386 Packages
uranium@Hex:~$ apt-cache policy do-release-upgrade
N: Unable to locate package do-release-upgrade

[uranium (uranium+ubuntu)]

OK, this problem is elsewhere. I started trying to upgrade because I was getting lockups on suspend as of having taken some updates--probably the wrong reaction, if e.g. a newer kernel is the problem. While debugging this upgrade problem, I also found lots of other ways to lock up my system [running lspci -k, starting the settings app, ...]. I've just tried booting into an older kernel [4.15.0-112 instead of 4.15.0-121] and suddenly everything works. Release notes show up, the upgrade seems happy to run. I haven't done the upgrade yet--might want to try a live-thumbdrive of the newer version to see if the kernel problem's there or not. But it's not the updater.

[uranium (uranium+ubuntu)]

Killing the bug as invalid, since it's elsewhere.