Re: automatic stacktrace on panic, was: Re: Boot fail as kvm guest

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Feb 17, 2012 at 02:36:16PM +0100, Marc Balmer wrote:
> So whenever ddb.commandonenter is set to a non-empty string, or the (not
> yet existing) ddb.stacktrace sysctl is set to 1, this should imply
> ddb.onpanic=1?
> 
> Although there are valid use cases for ddb.onpanic=0, I think it is
> wrong as a default.  The default should really be to enter ddb, and then
> output the backtrace.
> 
> Personally I prefer no magic at all, but changing the default of
> ddb.onpanic to 1, and introducing a new ddb.backtrace sysctl which
> defaults to 1.

This has already been discussed. ddb.onpanic is set to 0 so that
on panic, a system dumps core and reboots. I feel it could be
set back to one in HEAD and default to 0 only in releases.

As for automatically outputting stack trace on panic:
this can be a long output, much longer than a .e.g VGA display.
This means that the user has only the tail of the stack trace and
doesn't see the panic message, which, actually, is the most important.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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