From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932493AbcFTLNu (ORCPT ); Mon, 20 Jun 2016 07:13:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59639 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753012AbcFTLNo (ORCPT ); Mon, 20 Jun 2016 07:13:44 -0400 Date: Mon, 20 Jun 2016 13:12:43 +0200 From: Jan Kratochvil To: Andy Lutomirski Cc: Oleg Nesterov , Kees Cook , Borislav Petkov , "linux-kernel@vger.kernel.org" , X86 ML , Linus Torvalds , Pedro Alves , Roland McGrath Subject: Re: [PATCH] x86/ptrace: Remove questionable TS_COMPAT usage in ptrace Message-ID: <20160620111243.GA8689@host1.jankratochvil.net> References: <94bda8cd5f326ae5591c80fb5d7c1c22624accec.1466244711.git.luto@kernel.org> <177f65bb-dab9-9a1e-73a8-506904192bb2@palves.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <177f65bb-dab9-9a1e-73a8-506904192bb2@palves.net> User-Agent: Mutt/1.6.1 (2016-04-27) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 20 Jun 2016 11:12:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Jun 2016 12:07:56 +0200, Pedro Alves wrote: > On 06/18/2016 06:02 PM, Andy Lutomirski wrote: > > Yuck. I should have dug in to the history. Why not just > > unconditionally sign-extend eax when set by a 32-bit tracer? > > No idea. Roland McGrath knows why he wrote it that way, Cced. What if eax contains an address in 2GB..4GB range? I guess currently the orig_eax check tries to verify %eax cannot contain an address. Jan