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,URIBL_BLOCKED,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 0A738C43441 for ; Wed, 28 Nov 2018 14:29:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB84E2086B for ; Wed, 28 Nov 2018 14:29:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB84E2086B 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 S1728377AbeK2BbY (ORCPT ); Wed, 28 Nov 2018 20:31:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727789AbeK2BbY (ORCPT ); Wed, 28 Nov 2018 20:31:24 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A26B416972C; Wed, 28 Nov 2018 14:29:33 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.12]) by smtp.corp.redhat.com (Postfix) with SMTP id 5497A5EDE2; Wed, 28 Nov 2018 14:29:31 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 28 Nov 2018 15:29:33 +0100 (CET) Date: Wed, 28 Nov 2018 15:29:30 +0100 From: Oleg Nesterov To: "Dmitry V. Levin" Cc: Andy Lutomirski , Elvira Khabirova , Eugene Syromyatnikov , Steven Rostedt , Ingo Molnar , Kees Cook , Jann Horn , Michael Ellerman , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, strace-devel@lists.strace.io Subject: Re: [PATCH v4 2/2] ptrace: add PTRACE_GET_SYSCALL_INFO request Message-ID: <20181128142930.GF30395@redhat.com> References: <20181128130439.GB28206@altlinux.org> <20181128130715.GD28206@altlinux.org> <20181128141049.GD30395@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181128141049.GD30395@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 28 Nov 2018 14:29:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/28, Oleg Nesterov wrote: > > On 11/28, Dmitry V. Levin wrote: > > > > +static unsigned long > > +ptrace_get_syscall_info_entry(struct task_struct *child, > > + struct ptrace_syscall_info *info) > > +{ > > + struct pt_regs *regs = task_pt_regs(child); > > + unsigned long args[ARRAY_SIZE(info->entry.args)]; > > + int i; > > + > > + info->op = PTRACE_SYSCALL_INFO_ENTRY; > > + info->arch = syscall_get_arch(child); > > + info->entry.nr = syscall_get_nr(child, regs); > > + info->entry.instruction_pointer = instruction_pointer(regs); > > + info->entry.stack_pointer = user_stack_pointer(regs); > > + info->entry.frame_pointer = frame_pointer(regs); > > + syscall_get_arguments(child, regs, 0, ARRAY_SIZE(args), args); > > + for (i = 0; i < ARRAY_SIZE(args); i++) > > + info->entry.args[i] = args[i]; > > I must have missed something, Yes ;) I didn't look at info->entry.args, it is __u64[6]. > but why do we need the temporary args[], > syscall_get_arguments(..., info->entry.args) should equally work? > > Oleg.