From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752318Ab2AYXgp (ORCPT ); Wed, 25 Jan 2012 18:36:45 -0500 Received: from mail-ey0-f174.google.com ([209.85.215.174]:55290 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752244Ab2AYXgm (ORCPT ); Wed, 25 Jan 2012 18:36:42 -0500 From: Denys Vlasenko To: Pedro Alves Subject: Re: Compat 32-bit syscall entry from 64-bit task!? Date: Thu, 26 Jan 2012 00:36:35 +0100 User-Agent: KMail/1.8.2 Cc: Oleg Nesterov , Linus Torvalds , Indan Zupancic , Andi Kleen , Jamie Lokier , Andrew Lutomirski , Will Drewry , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, olofj@chromium.org, mhalcrow@google.com, dlaor@redhat.com, Roland McGrath References: <20120125193635.GA30311@redhat.com> <4F206420.5080200@redhat.com> In-Reply-To: <4F206420.5080200@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201201260036.35805.vda.linux@googlemail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 25 January 2012 21:20, Pedro Alves wrote: > On 01/25/2012 07:36 PM, Oleg Nesterov wrote: > > > > Not sure this is really better, but there is another idea. Currently we > > have PTRACE_O_TRACESYSGOOD to avoid the confusion with the real SIGTRAP. > > Perhaps we can add PTRACE_O_TRACESYS_VERY_GOOD (or we can look at > > PT_SEIZED instead) and report TS_COMPAT via ptrace_report_syscall ? > > May I beg to don't rely on PTRACE_SYSCALL for anything new? This doesn't *add* anything new. All the same ptrace stops will happen at exactly the same moments. No new stops added. We only add a value into upper half of waitpid status: (status >> 16) used to be 0 on syscall entry. Now it will be PTRACE_EVENT_SYSCALL_ENTRY[1]. That's all. > You can't PTRACE_SINGLESTEP and PTRACE_SYSCALL simultaneously. This is an orthogonal problem. -- vda