From owner-freebsd-hackers Fri Feb 27 18:57:32 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA28359 for freebsd-hackers-outgoing; Fri, 27 Feb 1998 18:57:32 -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 SAA28345 for ; Fri, 27 Feb 1998 18:57:22 -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 NAA04930; Sat, 28 Feb 1998 13:27:20 +1030 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.8.8/8.8.7) id MAA15941; Sat, 28 Feb 1998 12:48:44 +1030 (CST) (envelope-from grog) Message-ID: <19980228124844.00033@freebie.lemis.com> Date: Sat, 28 Feb 1998 12:48:44 +1030 From: Greg Lehey To: Mike Smith Cc: FreeBSD Hackers Subject: Re: Kernel debugging: what's going on here? References: <19980228123253.24049@freebie.lemis.com> <199802280214.SAA00165@dingo.cdrom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.89i In-Reply-To: <199802280214.SAA00165@dingo.cdrom.com>; from Mike Smith on Fri, Feb 27, 1998 at 06:14:02PM -0800 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 Fri, 27 February 1998 at 18:14:02 -0800, Mike Smith wrote: >> On Fri, 27 February 1998 at 17:56:46 -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? > > Whoops. OK, are we sure that "bp" points to the same type in both > cases? Not any more :-) Somebody else replied first. > And more importantly, that bp->b_vp is expected to be the same type? Yes, it was. > (Yes, this is *really* clutching at straws). There's not much else > short of a GDB bug that I can think of that would cause this. Thanks. I should have seen this myself, but sometimes you end up looking in the wrong place. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message