From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752242Ab2AYUWO (ORCPT ); Wed, 25 Jan 2012 15:22:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:65337 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751101Ab2AYUWM (ORCPT ); Wed, 25 Jan 2012 15:22:12 -0500 Message-ID: <4F206420.5080200@redhat.com> Date: Wed, 25 Jan 2012 20:20:48 +0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: Oleg Nesterov CC: 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 , Denys Vlasenko Subject: Re: Compat 32-bit syscall entry from 64-bit task!? References: <49017bd7edab7010cd9ac767e39d99e4.squirrel@webmail.greenhost.nl> <20120118015013.GR11715@one.firstfloor.org> <20120118020453.GL7180@jl-vm1.vm.bytemark.co.uk> <20120118022217.GS11715@one.firstfloor.org> <20120125193635.GA30311@redhat.com> In-Reply-To: <20120125193635.GA30311@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? You can't PTRACE_SINGLESTEP and PTRACE_SYSCALL simultaneously. Think of gdb single-stepping all the way for some reason (software watchpoints, for ex.), while at the same time wanting to catch syscalls. As Roland suggested, replacing PTRACE_SYSCALL with PTRACE_O_TRACE_SYSCALL_{ENTRY,EXIT} and PTRACE_EVENT_SYSCALL_{ENTRY,EXIT} would be superior, syscall tracing wise. -- Pedro Alves