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=-6.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 8A6C8C433DF for ; Wed, 19 Aug 2020 16:51:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7150A208DB for ; Wed, 19 Aug 2020 16:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726414AbgHSQvH (ORCPT ); Wed, 19 Aug 2020 12:51:07 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2674 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726211AbgHSQvF (ORCPT ); Wed, 19 Aug 2020 12:51:05 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id B4E5CE62BFCF43E078F0; Wed, 19 Aug 2020 17:51:02 +0100 (IST) Received: from [127.0.0.1] (10.47.1.203) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1913.5; Wed, 19 Aug 2020 17:51:02 +0100 Subject: Re: [REPORT] BUG: KASAN: use-after-free in bt_iter+0x80/0xf8 To: Ming Lei CC: "axboe@kernel.dk" , "linux-block@vger.kernel.org" , Christoph Hellwig References: <8376443a-ec1b-0cef-8244-ed584b96fa96@huawei.com> <20200819000009.GB2712797@T590> <585bb054-2009-4abc-f1e8-802e494ba49b@huawei.com> <20200819085843.GA2730150@T590> <83de2368-a122-3b9c-db15-63ea442eecd9@huawei.com> <20200819142147.GA2795390@T590> From: John Garry Message-ID: <165cddcd-ad2c-7022-cae2-7995db39e570@huawei.com> Date: Wed, 19 Aug 2020 17:48:41 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200819142147.GA2795390@T590> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.1.203] X-ClientProxiedBy: lhreml701-chm.china.huawei.com (10.201.108.50) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 19/08/2020 15:21, Ming Lei wrote: > I guess that elevator switch may have to be involved in your reproducer, stale > request which are freed before switching to new elevator can stay in tags->rqs[], > then these stale requests are retrieved when reading iostat before old request slots in > tags->rqs[] are reset. Yeah, just switching -> "none" seems to do it. If I hack the elevator code to default to "none", then no issue. Thanks