Experience with an unsupported kernel

Hi, I filed this bug in launchpad: https://bugs.launchpad.net/snappy/+bug/1709155

I wasn’t sure if you guys still used it for bugs (instead of this forum), even though the README.md file for snapd says to use launchpad.

Anyway, i’m reproducing the bug’s content below just in case you prefer to discuss it here.


If I’m running an unsupported kernel for snapd, like a default ubuntu trusty install for example, I get a cryptic error message very late in the process, only when I try to run something from a snap.

This is how far the tools let me go before outputting a cryptic error:

$ sudo apt install snapd
$ sudo snap install hello-world
$ snap list
$ hello-world
cannot perform readlinkat() on the mount namespace file descriptor of the init process: Permission denied

The snapd package correctly pulls in a newer kernel in this Trusty scenario (4.4.0), but nothing else says it has to be rebooted into. The user might even miss the fact that a newer kernel was installed.

Also the fact that snap commands like “snap install” and “snap list” work just fine add to the confusion that ensues when you try to run something from the snap. At first it looks like the snap itself is not working, and you might be tempted to file a bug against the snap.

Ideally, snapd should somehow tell the user that the running kernel is too old. How and where to send this message can be a bit complicated. Maybe with every snap command? Something like “Warning: your running kernel is unsupported, snaps may not work correctly” when running even “snap list”. If we can be very specific about kernel versioning here (considering snappy is not ubuntu exclusive), then even better.

1 Like

That’s a great suggestion, thanks.

If this is a desktop system and installing a new kernel did not cause a popup asking you to reboot, this is another bug … (on server installs the “Reboot required” message only shows up at the login prompt, but on desktops there should be a popup)

Great idea regarding the better message :+1: