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From: Archie Cobbs <archie@dellroad.org>
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In-Reply-To: <20030430142532.F3741@odysseus.silby.com>
To: Mike Silbersack <silby@silby.com>
Date: Wed, 30 Apr 2003 16:51:46 -0700 (PDT)
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cc: freebsd-net@FreeBSD.ORG
Subject: Re: Review needed: Mbuf double-free detection patch
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Mike Silbersack wrote:
> I'd be interested in comments on the attached patch from anyone who's been
> doing work with network drivers & such.  All it does is add a M_FREELIST
> flag which is set whenever a mbuf is freed.  If m_free or m_freem find
> this flag to be set, they will panic, as this is a clear sign that the
> mbuf was freed twice.  (All flags are cleared whenever a mbuf is
> taken off the freelist, so false M_FREELIST hits shouldn't occur.)

Without reviewing the patch, I like the idea a whole lot. We added
similar sanity checks at Vernier and they were very helpful.

-Archie

__________________________________________________________________________
Archie Cobbs     *     Precision I/O      *     http://www.precisionio.com