From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932498AbdKGIJV (ORCPT ); Tue, 7 Nov 2017 03:09:21 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:56836 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932418AbdKGIJS (ORCPT ); Tue, 7 Nov 2017 03:09:18 -0500 Subject: Re: [RFC PATCH] bpf: Add helpers to read useful task_struct members To: "Naveen N. Rao" , , Sandipan Das References: <20171103065833.8076-1-sandipan@linux.vnet.ibm.com> <94a4761f-1b51-8b70-fb7f-3cea91c69717@fb.com> <1509815348.8zu63uatdo.naveen@linux.ibm.com> <4acdc081-341d-ee91-a591-b1d331a8c8d5@fb.com> <1509982000.092la4257a.naveen@linux.ibm.com> CC: Brendan Gregg , , Martin KaFai Lau , Kees Cook , From: Alexei Starovoitov Message-ID: Date: Tue, 7 Nov 2017 17:08:41 +0900 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1509982000.092la4257a.naveen@linux.ibm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [2620:10d:c094:180::1:1f55] X-ClientProxiedBy: SG2PR01CA0097.apcprd01.prod.exchangelabs.com (2603:1096:3:15::23) To DM3PR15MB0971.namprd15.prod.outlook.com (2603:10b6:0:10::25) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 496ddaec-f849-4a45-2c98-08d525b6cdd8 X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(4534020)(4602075)(4627115)(201703031133081)(201702281549075)(2017052603249);SRVR:DM3PR15MB0971; 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Rao wrote: >> I thought such struct shouldn't change layout. >> If it is we need to fix include/linux/compiler-clang.h to do that >> anon struct as well. > > We considered that, but it looked to be very dependent on the version of > gcc used to build the kernel. But, this may be a simpler approach for > the shorter term. > why it would depend on version of gcc? We just need this, no? diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index de179993e039..4e29ab6187cb 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -15,3 +15,6 @@ * with any version that can compile the kernel */ #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) + +#define randomized_struct_fields_start struct { +#define randomized_struct_fields_end }; since offsets are mandated by C standard.