Okay, that's cool. Once the "unstuck" message appears, the problem has already gone away again.

And I guess it will always say "0.0 secs", so I'll change that message next time to show something more useful.

But the fact that you even saw it, indicates that jiffies took a pause somewhere -- kernel still running, but clock interrupts (for scheduler) not working, briefly.

That's the bug that might go away when I release my fix for Hugo's timer interrupt routine.

Cheers