From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4837 invoked by alias); 14 May 2008 18:16:47 -0000 Received: (qmail 4825 invoked by uid 22791); 14 May 2008 18:16:46 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 14 May 2008 18:16:19 +0000 Received: (qmail 7546 invoked from network); 14 May 2008 18:16:16 -0000 Received: from unknown (HELO orlando.local) (pedro@127.0.0.2) by mail.codesourcery.com with ESMTPA; 14 May 2008 18:16:16 -0000 From: Pedro Alves To: gdb-patches@sourceware.org Subject: Re: longjmp handling vs. glibc LD_POINTER_GUARD problems Date: Wed, 14 May 2008 19:17:00 -0000 User-Agent: KMail/1.9.9 Cc: "Ulrich Weigand" References: <200805141800.m4EI0IHe006471@d12av02.megacenter.de.ibm.com> In-Reply-To: <200805141800.m4EI0IHe006471@d12av02.megacenter.de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200805141916.23912.pedro@codesourcery.com> 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/msg00439.txt.bz2 A Wednesday 14 May 2008 19:00:18, Ulrich Weigand wrote: > I'm now wondering how we should handle this. Should be > implement an ad-hoc solution to retrieve the guard, which > may break in the future if glibc changes? Should we require > use of LD_POINTER_GUARD=0 (which switches off the pointer > guard mechanism) to enable debugging? Am I overlooking some > defined interface to get at the value? No, you're not. There is none. And still LD_POINTER_GUARD=0 doesn't help when attaching to an already running target. > Why are we using the get_longjmp_target mechanism instead of > just stepping through longjmp until we see where we come out? You tell me. :-) I had assumed there was a reason. Perhaps to support longjumping to a different stack, but that's hardly a portable and frequent use case. This seems to be the path to go. -- Pedro Alves