use MALLOC_PERTURB_ ... or lose

[David Malcolm]

On Wed, 2010-05-05 at 18:24 +0200, Michal Schmidt wrote:
> On Wed, 05 May 2010 17:30:29 +0200 Jim Meyering wrote:
> > I propose (seriously, now) to add this to /etc/profile,
> > or to some always-sourced file like /etc/profile.d/glibc.sh:
> > 
> >     # Enable glibc's malloc perturbing feature in Rawhide.
> >     # http://udrepper.livejournal.com/11429.html
> >     read _f _r _n _code_name < /etc/redhat-release &&
> >     case $_code_name in
> >         *Rawhide*) export MALLOC_PERTURB_=$((RANDOM % 255 + 1)) ;;
> >     esac
> 
> Would export MALLOC_CHECK_=3 be a useful addition too?

I like the idea of rawhide-only debug checks like this, but can we add
some kind of message to login like this:

<idea>
This is a pre-release version of Fedora, and is running with extra
diagnostics that help find bugs, but impact performance.

Please read
(LINK TO A WIKI PAGE)
before attempting to run benchmarks on this system.
</idea>

Is there a good place to add this?  e.g. /etc/issue ?  I'm not sure of
how to handle a conditional there.

Dave