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 11:51:12AM -0500, Thor Lancelot Simon wrote:
> On Fri, Feb 17, 2012 at 02:21:57PM +0100, Marc Balmer wrote:
> > Am 17.02.12 14:16, schrieb Hubert Feyrer:
> > > On Fri, 17 Feb 2012, Marc Balmer wrote:
> > >>> I think NetBSD should add a stack trace on panics automatically...
> > >>
> > >> Can't that be achieved using ddb.commandonenter ?
> > >> Or should a ddb.stacktrace sysctl variable be introduced for this?
> > > 
> > > Whatever one, it should be on by default.
> > > Each time we have to ask people to give us information, this is 
> > > suboptimal.
> > 
> > So what is the best way (I am now collecting opinions)?
> > 
> > 1) Introduce a new sysctl ddb.stacktrace, which is on by default
> > 2) Set ddb.commandonenter to 'bt' by default
> 
> While #2 is appealing, in practice I have seen it cause systems to get
> stuck in a panic loop.  So, please don't do #2.

1) would probably have the same problem, unless we make sure to not reenter
ddb from itself, which would also fix the loop in 2).

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