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=-0.7 required=3.0 tests=FORGED_MUA_MOZILLA, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 9DF48C433E1 for ; Wed, 10 Jun 2020 06:34:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84FF720825 for ; Wed, 10 Jun 2020 06:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726180AbgFJGe6 (ORCPT ); Wed, 10 Jun 2020 02:34:58 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:40274 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726035AbgFJGe5 (ORCPT ); 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Wed, 10 Jun 2020 06:34:36 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05A6YYIq57540632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jun 2020 06:34:34 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 00B7811C054; Wed, 10 Jun 2020 06:34:34 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 354E411C04A; Wed, 10 Jun 2020 06:34:32 +0000 (GMT) Received: from localhost.localdomain (unknown [9.199.37.89]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 10 Jun 2020 06:34:32 +0000 (GMT) Subject: Re: [PATCHv2 1/1] ext4: mballoc: Use this_cpu_read instead of this_cpu_ptr To: Christoph Hellwig , tytso@mit.edu Cc: linux-ext4@vger.kernel.org, jack@suse.com, Hillf Danton , linux-fsdevel@vger.kernel.org, Borislav Petkov , Marek Szyprowski , syzbot+82f324bb69744c5f6969@syzkaller.appspotmail.com References: <534f275016296996f54ecf65168bb3392b6f653d.1591699601.git.riteshh@linux.ibm.com> <20200610062538.GA24975@infradead.org> From: Ritesh Harjani Date: Wed, 10 Jun 2020 12:04:31 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200610062538.GA24975@infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <20200610063432.354E411C04A@d06av25.portsmouth.uk.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-06-10_02:2020-06-10,2020-06-10 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=845 spamscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 bulkscore=0 impostorscore=0 mlxscore=0 phishscore=0 adultscore=0 cotscore=-2147483648 malwarescore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006100049 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 6/10/20 11:55 AM, Christoph Hellwig wrote: > On Tue, Jun 09, 2020 at 04:23:10PM +0530, Ritesh Harjani wrote: >> Simplify reading a seq variable by directly using this_cpu_read API >> instead of doing this_cpu_ptr and then dereferencing it. >> >> This also avoid the below kernel BUG: which happens when >> CONFIG_DEBUG_PREEMPT is enabled > > I see this warning all the time with ext4 using tests VMs, so lets get > this fixed ASAP before -rc1: Couldn't agree more. > > Reviewed-by: Christoph Hellwig > Thanks -ritesh