:: Re: [Dng] Linux boot documentation
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Auteur: Jürgen Buchmüller
Datum:  
Aan: dng
Onderwerp: Re: [Dng] Linux boot documentation
Am Dienstag, den 05.05.2015, 11:22 +0200 schrieb Didier Kryn:
> I'm not sure what happens if init crashes after other processes have
> been started, wether the kernel panics or other processes continue
> without init - not a very good situation.


FWIW: I've seen this happening with a home grown jessie (RC2) for
Cubietruck (armv7hf) where a module was seriously broken and led to a
segfault.

Since with systemd modules seem to be loaded by pid 1 itself, the crash
takes down systemd with it and the system reboots after exiting pid 1,
just crash again when trying to load the broken module the next time. No
chance to break out of this loop AFAIK.

To me this looks like a fundamental design flaw. A crashing module
should never _ever_ take the whole system down. There has to be some
privilege separation and signal handling in place to prevent that.

With SysV init this is no big problem, as usually some child process of
init (a shell script) loads the detected (udev rules) or defined
(/etc/modules) modules and if it crashes, init will still be alive.

Jürgen

P.S.: It may be that I did something wrong myself, while I basically
just debootstrapped jessie to an SD card image and added some custom
modules to the system.