From owner-freebsd-hackers Fri Feb 27 18:58:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA28476 for freebsd-hackers-outgoing; Fri, 27 Feb 1998 18:58:39 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id SAA28346 for ; Fri, 27 Feb 1998 18:57:23 -0800 (PST) (envelope-from grog@lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.8.7/8.8.5) with ESMTP id NAA04927; Sat, 28 Feb 1998 13:27:19 +1030 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.8.8/8.8.7) id MAA15924; Sat, 28 Feb 1998 12:45:45 +1030 (CST) (envelope-from grog) Message-ID: <19980228124544.45624@freebie.lemis.com> Date: Sat, 28 Feb 1998 12:45:44 +1030 From: Greg Lehey To: Mike Smith Cc: FreeBSD Hackers Subject: Re: Kernel debugging: what's going on here? References: <19980228122110.36590@freebie.lemis.com> <199802280156.RAA29982@dingo.cdrom.com> <19980228123253.24049@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.89i In-Reply-To: <19980228123253.24049@freebie.lemis.com>; from Greg Lehey on Sat, Feb 28, 1998 at 12:32:53PM +1030 WWW-Home-Page: http://www.lemis.com/~grog Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 28 February 1998 at 12:32:53 +1030, Greg Lehey wrote: > On Fri, 27 February 1998 at 17:56:46 -0800, Mike Smith wrote: >>> On Fri, 27 February 1998 at 17:45:39 -0800, Mike Smith wrote: >> Yes, I noticed. But rewriting the bp on the fly is not uncommon; quite >> a few device drivers do it, it wouldn't surprise me if it wasn't done >> elsewhere rather than cloning the original. > > Sure, all sorts of things modify the buffer header. But you're still > missing the point: the processor is stopped here, it's in the > debugger. No instructions were executed between the two views. You > might just as well take a look at a dump. Since when does the content > of memory differ depending on where you look at it from? Found! thanks to the help of a private reply. For some reason, my struct vnode looks different in each frame. I was using the pointer in the buf header instead of the absolute address. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message