From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750709AbWFWOAw (ORCPT ); Fri, 23 Jun 2006 10:00:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750708AbWFWOAn (ORCPT ); Fri, 23 Jun 2006 10:00:43 -0400 Received: from 1wt.eu ([62.212.114.60]:17929 "EHLO 1wt.eu") by vger.kernel.org with ESMTP id S1750709AbWFWOAh (ORCPT ); Fri, 23 Jun 2006 10:00:37 -0400 Date: Fri, 23 Jun 2006 15:52:01 +0200 From: Willy Tarreau To: Andi Kleen Cc: pageexec@freemail.hu, marcelo@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86_64: another fix for canonical RIPs during signal handling Message-ID: <20060623135201.GB24737@1wt.eu> References: <449BC808.4174.277D15CF@pageexec.freemail.hu> <449C0616.4382.286F7C8C@pageexec.freemail.hu> <20060623133217.GA24737@1wt.eu> <200606231546.21731.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200606231546.21731.ak@suse.de> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 23, 2006 at 03:46:21PM +0200, Andi Kleen wrote: > > > If I understand it well, an application which maps address 0 has no way to > > be notified that the kernel detected a corrupted stack pointer. > > It will just not crash again after the application tried to deliberately > crash the kernel. "deliberately" is a bit exagerated here. Failed stack overflows, hardware memory corruption and various bugs that happen to most application developpers at early coding stage are not what can be called "deliberate". Also, I don't know if memory leak detectors rely on getting a SEGV, but this patch would make them useless on apps which map addr 0. > > I agree > > that if the proposed patch avoids to make this undesired distinction between > > apps that map addr 0 and those which don't, it would be better to merge it. > > Andi, you said there was nothing wrong with it, do you accept that it gets > > merged ? > > As I said, it's not wrong, just not necessary. I understand your point, but I think that covering most situations the same way helps reducing exceptions, and helps troubleshooting. > -Andi Regards, Willy