From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932635Ab1ESWmR (ORCPT ); Thu, 19 May 2011 18:42:17 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:47980 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932323Ab1ESWmQ (ORCPT ); Thu, 19 May 2011 18:42:16 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=from:to:subject:date:user-agent:cc:references:in-reply-to :mime-version:content-type:content-transfer-encoding :content-disposition:message-id; b=Qn4BIPyyFmG/U9Gf+Ggtb/XIVt13gUlFG1y2WvoyfaFZdlApLWaYHkpP81SSoclqSK /OtgAhKBqLe8epPkwVOCieXm3S08sHrjUOkBTWJ4bCNUCz1a8sQfJ6VcN9bn0ES/XMpo KGb/eGj776KsgpBIGtq84iy3/SbML74327aSw= From: Denys Vlasenko To: Pedro Alves Subject: Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE Date: Fri, 20 May 2011 00:42:12 +0200 User-Agent: KMail/1.8.2 Cc: Tejun Heo , 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> <20110519141728.GJ627@htj.dyndns.org> <201105192031.33569.pedro@codesourcery.com> In-Reply-To: <201105192031.33569.pedro@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201105200042.12230.vda.linux@googlemail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 19 May 2011 21:31, Pedro Alves wrote: > 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. SEIZE,fork-in-tracee,INTERRUPT sequence is indistinguishable from SEIZE happening two microseconds later: fork-in-tracee,SEIZE,INTERRUPT > In GDBs case, GDB will want to poke at memory > right after attaching ...where "right after attaching" is defined as "when the first ptrace-stop is reported". Which will happen very soon. -- vda