Re: [PATCH 4/5] don't panic if /sbin/init exits or killed

[Oleg Nesterov <oleg@tv-sign.ru>]

On 03/16, Roland McGrath wrote:
>
> > But panic() isn't better? It doesn't provide any useful info.
> 
> It is not misleading in the same way.  It's clear that going to look at the
> kernel source is not the place to find the root of the problem.
> 
> > Well, I think the generic "if we have a chance to survive, we should try
> > to survive" rule is good.
> > 
> > If the boot init dies, at least the admin has a chance to figure out what
> > has happened, and -o remount,ro /.
> 
> For me and you, I agree.  I think the common case is that there is no admin
> prepared to do any such thing, but just someone expecting a reboot to fix
> things and preferring that a failing system reboot itself in the middle of
> the night rather than wedge.

Agreed,

> > Every BUG/BUG_ON in fact means the system is not useable, but still it does
> > not panic(), but tries to proceed.
> 
> Many production systems probably set panic_on_oops.  Having the init panic
> behavior keyed on that seems fine to me.  I just don't like the "kernel bug
> at this source line" output when it's not true.

Ah, OK. We can change this to dump_stack() without BUG().

(but again! panic() isn't better, it also looks like a kernel bug).

Oleg.