'snap refresh pc-kernel' hangs on mantic FDE install

[Steve Langasek]

Mantic TPM FDE install using canary image 20230825.2.

This ships with pc-kernel version 1393. Therefore there is a newer version, 1397, that can be refreshed to.

Running 'sudo snap refresh pc-kernel' from the commandline returns:
  2023-08-26T03:54:46Z INFO Task set to wait until a manual system restart allows to continue
  WARNING: pressing crtl-c will abort the running change.
  Handling re-refresh of "pc-kernel as needed"

with a spinner that runs endlessly.

It is unclear what the user is expected to do to continue.

If I reboot from the desktop boot menu, it does successfully reboot to 1397.

The UX should be improved here. Instead of spinning interminably, the snap command should return with clear instructions that the user should reboot to finish.

[Steve Langasek (vorlon)]

Note that clarifying the language about a manual reboot does not by itself address this issue. In some scenarios, a user may have only a serial console from which to issue commands to the system; a `snap` command spinning indefinitely then blocks the user from issuing a reboot command.

[Philip Meulengracht (the-meulengracht)]

Thank you for reporting this issue, this is the current design of how we handle changes that require rebooting on Desktop. However it's unfortunate that it's actually ending up blocking people, and especially when a user only have a serial console.

We'll quickly investigate this, and decide on how we want to resolve this. I'll get back to you all!

*EDIT* So we actually have a fix for this currently in master (fixed in this PR https://github.com/snapcore/snapd/pull/12910), so it will be included in release 2.61

[Jean-Baptiste Lallement (jibel)]

Adding a task for update-notifier. When the kernel is upgraded, there should be a notification in the top panel.

[Łukasz Zemczak (sil2100)]

The notification should be there, since this should have been landed in mantic via:
https://bugs.launchpad.net/ubuntu/+source/update-notifier/+bug/1998947

I'll reach out to Nick to see what could be the problem here.

[Nick Rosbrook (enr0n)]

Note that the reboot notification from update-notifier would only show up after 3 hours. Was enough time given for that to have happened?

[Jean-Baptiste Lallement (jibel)]

Certainly not, I'll try again and wait 3 hours

[Jean-Baptiste Lallement (jibel)]

Actually, I received the notification on resume from suspend i.e. several hours after installation. I'll close the update-notifier task then. Sorry for the confusion.