Canonical Livepatch Client

Client stops applying patches with "cannot execute finitModule syscall: required key not available"

Bug #1833566 reported by Robie Basak on 2019-06-20

This bug affects 5 people

Affects		Status	Importance	Assigned to	Milestone
	Canonical Livepatch Client	Confirmed	Undecided	Unassigned

Bug Description

With linux-image-generic 4.4.0.151.159 installed and a boot time of approximately 26 May, on 17 June canonical-livepatch failed with:

Jun 17 21:49:58 mal canonical-livepatch[3092]: Client.Check
Jun 17 21:49:58 mal canonical-livepatch[3092]: Checking with livepatch service.
Jun 17 21:49:58 mal canonical-livepatch[3092]: updating last-check
Jun 17 21:49:58 mal canonical-livepatch[3092]: touched last check
Jun 17 21:49:58 mal canonical-livepatch[3092]: Applying update 52.3 for 4.4.0-148.174-generic
Jun 17 21:49:58 mal canonical-livepatch[3092]: during refresh: cannot apply patches: cannot apply update: cannot execute finitModule syscall: required key not available

Since then, I periodically see the following in my logs:

Jun 20 13:50:07 mal canonical-livepatch[3092]: Client.Check
Jun 20 13:50:07 mal canonical-livepatch[3092]: Checking with livepatch service.
Jun 20 13:50:07 mal canonical-livepatch[3092]: updating last-check
Jun 20 13:50:07 mal canonical-livepatch[3092]: touched last check
Jun 20 13:50:07 mal canonical-livepatch[3092]: No updates available at this time.
Jun 20 13:50:07 mal canonical-livepatch[3092]: Module may have caused kernel crash! Not inserting module.
Jun 20 13:50:07 mal canonical-livepatch[3092]: To override this warning, remove /var/snap/canonical-livepatch/common/locks/livepatch_Ubuntu_4_4_0_148_174_generic_52_52.3
Jun 20 13:50:07 mal canonical-livepatch[3092]: during refresh: cannot apply patches: lock file "/var/snap/canonical-livepatch/common/locks/livepatch_Ubuntu_4_4_0_148_174_generic_52_52.3" already exists

Expected behaviour: livepatch continues to function without user intervention

Actual behaviour: livepatch seems to require some kind of user intervention here to continue operation

This isn't just me: on searching, I found the same report at https://askubuntu.com/q/1152398/7808

It seems too coincidental to me that this independent report displays logs with a very similar failure time, and therefore I speculate that it's a systemic problem caused by some specific update or change rather than a problem specific to my system.

I can hold off rebooting for a few days if you'd like help debugging.

If it's a transient error that can be fixed, I'd appreciate some instructions on what is safe to do (overriding a warning talking of kernel crashes doesn't feel safe).