From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934476Ab1ESTiU (ORCPT ); Thu, 19 May 2011 15:38:20 -0400 Received: from mail.codesourcery.com ([38.113.113.100]:49268 "EHLO mail.codesourcery.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933830Ab1ESTiS (ORCPT ); Thu, 19 May 2011 15:38:18 -0400 X-Greylist: delayed 402 seconds by postgrey-1.27 at vger.kernel.org; Thu, 19 May 2011 15:38:18 EDT From: Pedro Alves Organization: CodeSourcery To: Tejun Heo Subject: Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE Date: Thu, 19 May 2011 20:31:33 +0100 User-Agent: KMail/1.13.5 (Linux/2.6.35-28-generic; KDE/4.6.2; x86_64; ; ) Cc: Denys Vlasenko , oleg@redhat.com, jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, indan@nul.nu, bdonlan@gmail.com References: <1305569849-10448-1-git-send-email-tj@kernel.org> <20110518095539.GU20624@htj.dyndns.org> <20110519141728.GJ627@htj.dyndns.org> In-Reply-To: <20110519141728.GJ627@htj.dyndns.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201105192031.33569.pedro@codesourcery.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 19 May 2011 15:17:28, Tejun Heo wrote: > But making SEIZE not trigger INTERRUPT and SETOPTIONS without > requiring TRACED don't seem too difficult. Jan, would that be enough? > Oleg, what do you think? UUIC, that opens a race where between SEIZEing and SETOPTIONS(O_TRACE FORK|VFORK|EXEC...), the tracee can fork/vfork/clone/exec, without the tracer getting the nice corresponding PTRACE_EVENT_ events. In GDBs case, GDB will want to poke at memory right after attaching, to at least read the loaded DSO list, so if you can't read tracee memory without interrupting it, you won't get much benefit from SEIZE not interrupting. Not to say other users wouldn't benefit. -- Pedro Alves