From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 171CFC43441 for ; Thu, 29 Nov 2018 15:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA73C2145D for ; Thu, 29 Nov 2018 15:03:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA73C2145D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729012AbeK3CJN (ORCPT ); Thu, 29 Nov 2018 21:09:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33838 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728495AbeK3CJM (ORCPT ); Thu, 29 Nov 2018 21:09:12 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D629E83F3E; Thu, 29 Nov 2018 15:03:33 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.12]) by smtp.corp.redhat.com (Postfix) with SMTP id F1B6C842A7; Thu, 29 Nov 2018 15:03:28 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 29 Nov 2018 16:03:33 +0100 (CET) Date: Thu, 29 Nov 2018 16:03:28 +0100 From: Oleg Nesterov To: Andy Lutomirski Cc: "Dmitry V. Levin" , Kees Cook , Jann Horn , Michael Ellerman , Elvira Khabirova , Eugene Syromiatnikov , Steven Rostedt , LKML , Linux API , Ingo Molnar , strace-devel@lists.strace.io Subject: Re: [PATCH v4 1/2] ptrace: save the type of syscall-stop in ptrace_message Message-ID: <20181129150327.GC10645@redhat.com> References: <20181128130439.GB28206@altlinux.org> <20181128130601.GC28206@altlinux.org> <20181128134913.GC30395@redhat.com> <20181128140533.GF28206@altlinux.org> <20181128142006.GE30395@redhat.com> <20181128152346.GG28206@altlinux.org> <20181128221125.GA2800@altlinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 29 Nov 2018 15:03:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/28, Andy Lutomirski wrote: > > I don't like any of this at all. Can we please choose a sensible API > design and let the API drive the implementation instead of vice versa? I too do not understand your concerns... > ISTM the correct solution is to add some new state to task_struct for > this. Sure we can do this. I have argued with the previous version not because the new member blows the task_struct. Although I think it is better to avoid this if possible. But this doesn't affect the API. Yes, this version uses ->ptrace_message but I think this is _good_ exactly because it is already visible to userspace, so if debugger only needs to distinguish syscall entry/exit it can simply use PTRACE_GETEVENTMSG without PTRACE_GET_SYSCALL_INFO. > If we're concerned about making task_struct bigger, I have a > half-finished patch to factor all the ptrace tracee state into a > separate struct. I even sent the patch(es) which does this several years ago ;) Oleg.