bug#22548: Kernel panic after system reconfiguration

[Ludovic Courtès]

Alex Kost <address@hidden> skribis:

> And as reported by several people on #guix (I count at least 4 including
> me and Mark) a wrong swap device leads to a kernel panic if shepherd is
> used as the init system.
>
> Until I realized that it was a wrong swap, I made bisecting on shepherd
> to find out which commit introduced this bug.  It gave me commit
> 852341e¹: when I reconfigured my system (with a wrong swap) using
> shepherd on this commit, I had a kernel panic, while with shepherd on
> the previous commit the system booted successfully.
>
> ¹ 
> http://git.savannah.gnu.org/cgit/shepherd.git/commit/?id=852341ed0c08941cbdd022135f8bef7be2d7ec54

Ooooh, it took me a while but I see how this happens.  This is because
we start services directly from the config file, and anything that goes
wrong there is uncaught, which leads to this:

--8<---------------cut here---------------start------------->8---
Service udev has been started.
srfi-34(#<condition &action-runtime-error [service: #<<service> 184b150> 
action: start key: system-error arguments: ("swapon" "~S: ~A" 
("/dev/disk/foobar" "No such file or directory") (2))] 1ea24c0>)
[    6.856167] Kernel panic - not syncing: Attempted to kill init! 
exitcode=0x00000100
[    6.856167] 
[    6.856869] CPU: 0 PID: 1 Comm: shepherd Not tainted 4.4.1-gnu #1
[    6.857319] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 
rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
--8<---------------cut here---------------end--------------->8---

Ludo’.