Date: Tue, 3 Mar 1998 08:12:17 +1030 From: Greg Lehey <grog@lemis.com> To: Julian Elischer <julian@whistle.com> Cc: Mike Smith <mike@smith.net.au>, FreeBSD Hackers <hackers@FreeBSD.ORG> Subject: Re: Kernel debugging: what's going on here? Message-ID: <19980303081217.61608@freebie.lemis.com> In-Reply-To: <34FAFF9C.59E2B600@whistle.com>; from Julian Elischer on Mon, Mar 02, 1998 at 10:51:08AM -0800 References: <19980228123253.24049@freebie.lemis.com> <199802280214.SAA00165@dingo.cdrom.com> <19980228124844.00033@freebie.lemis.com> <34FAFF9C.59E2B600@whistle.com>
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On Mon, 2 March 1998 at 10:51:08 -0800, Julian Elischer wrote: > Greg Lehey wrote: >> >> 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. > > Ah struct vnode changed recently... Right. > didi you do a 'make depend' ? > > bet it didn't recompile some source... Worse. I found the @ directory pointing into the wrong tree. Logical, once you uknow where to look, but I was really beginning to suspect gdb. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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