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Date: Sat, 13 May 2006 11:03:37 -0500
From: "Matthew D. Fuller" <fullermd@over-yonder.net>
To: Kris Kennaway <kris@obsecurity.org>
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Cc: freebsd-stable@FreeBSD.org
Subject: Re: INVARIANTS (was Re: RELENG_4 -> 5 -> 6: significant performance
	regression)
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On Sat, May 13, 2006 at 11:58:26AM -0400 I heard the voice of
Kris Kennaway, and lo! it spake thus:
> 
> FYI, INVARIANTS adds checks but does not (is not supposed to) divert
> code paths.

It does at least in UMA; it does a lot of bzero()/NULL'ing out of
memory, which might hide later uninitialized-use bugs that could bite
you without it (and, of course, probably burns a fair chunk of CPU to
do it ;).  I know I've heard other cases over the past 5 years or so;
that's the only one I've heard recently or can check, but I wouldn't
be too surprised if there were others.


-- 
Matthew Fuller     (MF4839)   |  fullermd@over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.