From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1320 invoked by alias); 21 May 2008 22:16:11 -0000 Received: (qmail 1310 invoked by uid 22791); 21 May 2008 22:16:10 -0000 X-Spam-Check-By: sourceware.org Received: from NaN.false.org (HELO nan.false.org) (208.75.86.248) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 21 May 2008 22:15:51 +0000 Received: from nan.false.org (localhost [127.0.0.1]) by nan.false.org (Postfix) with ESMTP id 101F0983FF; Wed, 21 May 2008 22:15:49 +0000 (GMT) Received: from caradoc.them.org (22.svnf5.xdsl.nauticom.net [209.195.183.55]) by nan.false.org (Postfix) with ESMTP id E45A198371; Wed, 21 May 2008 22:15:48 +0000 (GMT) Received: from drow by caradoc.them.org with local (Exim 4.69) (envelope-from ) id 1Jywb6-0003G9-4m; Wed, 21 May 2008 18:15:48 -0400 Date: Thu, 22 May 2008 15:34:00 -0000 From: Daniel Jacobowitz To: Pedro Alves Cc: gdb-patches@sourceware.org, Ulrich Weigand Subject: Re: [patch] Re: longjmp handling vs. glibc LD_POINTER_GUARD problems Message-ID: <20080521221548.GA12402@caradoc.them.org> Mail-Followup-To: Pedro Alves , gdb-patches@sourceware.org, Ulrich Weigand References: <200805211920.m4LJKJXS016101@d12av02.megacenter.de.ibm.com> <200805212038.02924.pedro@codesourcery.com> <200805212301.26050.pedro@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200805212301.26050.pedro@codesourcery.com> User-Agent: Mutt/1.5.17 (2008-05-11) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2008-05/txt/msg00653.txt.bz2 On Wed, May 21, 2008 at 11:01:25PM +0100, Pedro Alves wrote: > Hmmm, I got blocked getting that to work. It always stops stepping > before getting to the other side. It looks like going out of > longjmp, the frame id of the longjmp's caller starts > being computed differently, or badly... This is the same problem as software watchpoints... I just don't think we're going to be able to get it to work. I certainly had to do horrible things on powerpc-linux when I wanted to be able to backtrace from epilogues without a symbol table. Which frame IDs are we comparing here? I think we can assume that longjmp is not going to change stacks until it's about to return, although the return might be on a different stack entirely. I suspect we'll be prone to stopping in the last instruction or two of longjmp, instead of returning the compiler. -- Daniel Jacobowitz CodeSourcery