From owner-freebsd-current@FreeBSD.ORG  Mon Dec 11 23:09:26 2006
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
X-Original-To: current@freebsd.org
Delivered-To: freebsd-current@FreeBSD.ORG
Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 39F9716A407
	for <current@freebsd.org>; Mon, 11 Dec 2006 23:09:26 +0000 (UTC)
	(envelope-from julian@elischer.org)
Received: from outQ.internet-mail-service.net (outQ.internet-mail-service.net
	[216.240.47.240])
	by mx1.FreeBSD.org (Postfix) with ESMTP id CB30043CB4
	for <current@freebsd.org>; Mon, 11 Dec 2006 23:08:06 +0000 (GMT)
	(envelope-from julian@elischer.org)
Received: from shell.idiom.com (HELO idiom.com) (216.240.47.20)
	by out.internet-mail-service.net (qpsmtpd/0.32) with ESMTP;
	Mon, 11 Dec 2006 14:54:40 -0800
Received: from [10.251.18.229] (nat.ironport.com [63.251.108.100])
	by idiom.com (8.12.11/8.12.11) with ESMTP id kBBN9OcR069659
	for <current@freebsd.org>; Mon, 11 Dec 2006 15:09:24 -0800 (PST)
	(envelope-from julian@elischer.org)
Message-ID: <457DE51C.905@elischer.org>
Date: Mon, 11 Dec 2006 15:09:16 -0800
From: Julian Elischer <julian@elischer.org>
User-Agent: Thunderbird 1.5.0.8 (Macintosh/20061025)
MIME-Version: 1.0
To: FreeBSD Current <current@freebsd.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: 
Subject: kdb_backtrace 'feature'?
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 11 Dec 2006 23:09:26 -0000

I often have the following:


code x() does some bad thing 'A'.. it's a known thing and you can tell
where it was done from (x()) but x() tell at the time that it is bad.

at some later time, you discover 'A' is bad but now you don't know who
was teh bad caller of x()


The solution I'm looking for:

when x() is called it calls kdb_backtrace, but has teh backtrace written 
to a static 16K buffer instead of being put out the normal way.

when A is found to be wrong, we can see who the last caller of x() was
and how it was called.


I am looking at it now.. but if anyone has any thoughts let me know...