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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 4A412C433E0 for ; Sat, 6 Jun 2020 03:10:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B6A920723 for ; Sat, 6 Jun 2020 03:10:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728567AbgFFDDS (ORCPT ); Fri, 5 Jun 2020 23:03:18 -0400 Received: from mga14.intel.com ([192.55.52.115]:15627 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728390AbgFFDDS (ORCPT ); Fri, 5 Jun 2020 23:03:18 -0400 IronPort-SDR: 1PBqU7sDNs4OOz5KaiqMstFDSwrFpOnYZ3UnHHTyPhlFXhFSBeL20t5YfceHktlcF/gT9fCsJ8 Qlbe5Uzea8pQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2020 20:03:18 -0700 IronPort-SDR: wEF+1kd51aRzfdSObmlDpRVOambjQk0OeFZRP2myEztEe1jvDy6ZrDWeWy22bg2VV21s7c7u/T UwKN/FYnPl2w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,478,1583222400"; d="scan'208";a="294885055" Received: from wdu1-mobl3.ccr.corp.intel.com (HELO [10.255.30.207]) ([10.255.30.207]) by fmsmga004.fm.intel.com with ESMTP; 05 Jun 2020 20:03:14 -0700 Subject: Re: [net] a6211caa63: dmesg.UBSAN:signed-integer-overflow_in_arch/x86/include/asm/atomic.h To: Peter Zijlstra , Eric Dumazet Cc: Yuqi Jin , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Jakub Kicinski , Jiri Pirko , Arvind Sankar , Jiong Wang , Shaokun Zhang , LKML , lkp@lists.01.org References: <20200605080929.GK12456@shao2-debian> <20200605140521.GD4117@hirez.programming.kicks-ass.net> From: "Chen, Rong A" Message-ID: Date: Sat, 6 Jun 2020 11:03:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200605140521.GD4117@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/5/2020 10:05 PM, Peter Zijlstra wrote: > On Fri, Jun 05, 2020 at 06:17:51AM -0700, Eric Dumazet wrote: >> On Fri, Jun 5, 2020 at 1:10 AM kernel test robot wrote: >> There you go. >> >> We decided this was a bogus report, and that UBSAN requires sane compilers. >> >> Please read the fine comment that was added in this commit and update >> your compiler or do not mess with compiler flags. >> >> + /* If UBSAN reports an error there, please make sure your compiler >> + * supports -fno-strict-overflow before reporting it that was a bug >> + * in UBSAN, and it has been fixed in GCC-8. >> + */ >> + return atomic_add_return(segs + delta, p_id) - segs; >>> make HOSTCC=gcc-4.9 CC=gcc-4.9 ARCH=i386 olddefconfig prepare modules_prepare bzImage > Rong, can you make sure to exclude gcc<8 for UBSAN reports ? Got it, thank's for your warning. Best Regards, Rong Chen