From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13292 invoked by alias); 14 Oct 2003 16:18:11 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 13285 invoked from network); 14 Oct 2003 16:18:10 -0000 Received: from unknown (HELO nevyn.them.org) (66.93.172.17) by sources.redhat.com with SMTP; 14 Oct 2003 16:18:10 -0000 Received: from drow by nevyn.them.org with local (Exim 4.24 #1 (Debian)) id 1A9RsA-00031a-2d for ; Tue, 14 Oct 2003 12:18:10 -0400 Date: Tue, 14 Oct 2003 16:18:00 -0000 From: Daniel Jacobowitz To: gdb-patches@sources.redhat.com Subject: Re: problem unwinding past pthread_cond_wait() on x86 RedHat 9.0 Message-ID: <20031014161810.GA11573@nevyn.them.org> Mail-Followup-To: gdb-patches@sources.redhat.com References: <20031014054225.GB919@gnat.com> <20031014125731.GA14097@nevyn.them.org> <3F8C1523.5040704@redhat.com> <20031014154649.GA989@gnat.com> <20031014155211.GB10669@nevyn.them.org> <3F8C2139.3040904@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F8C2139.3040904@redhat.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-10/txt/msg00462.txt.bz2 On Tue, Oct 14, 2003 at 12:15:53PM -0400, Andrew Cagney wrote: > >On Tue, Oct 14, 2003 at 08:46:49AM -0700, Joel Brobecker wrote: > > > >>> Joel, what happens if you type: > >>> > >>> (gdb) x/i 0xffffe002 > > > >> > >>Something like "Cannot read memory at 0xffffe002" (already tried it :-). > >>What is this address, BTW. I always wondered... Kernel code? Special > >>address? > > > > > >Search for "vsyscall DSO" in the gdb@ archives to learn more than you > >ever wanted to know :) Patches to fully support it are still pending. > > No. > > No matter how much you patch GDB, GDB isn't going to dig itself out of > thishole. It's not able to access the code/data/whatever at that > address so it's never going to correctly unwind from it. > > Kernel bug - incomplete functionality. We're both right. Patches for this are still pending. They'll fix the unwinding when using a 2.6 kernel which _does_ let the page be accessed. At that point I wouldn't be surprised if you folks at RH published an errata kernel which let this work in RH9, or RH10 or whatever it is now. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer