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=-5.3 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 3575AC433B4 for ; Wed, 28 Apr 2021 15:52:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED5EC613BF for ; Wed, 28 Apr 2021 15:52:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229961AbhD1Pxj (ORCPT ); Wed, 28 Apr 2021 11:53:39 -0400 Received: from mail-pg1-f182.google.com ([209.85.215.182]:37720 "EHLO mail-pg1-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240526AbhD1Pww (ORCPT ); Wed, 28 Apr 2021 11:52:52 -0400 Received: by mail-pg1-f182.google.com with SMTP id p2so29577808pgh.4 for ; Wed, 28 Apr 2021 08:52:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=h/zzIdjrrUl2/UsHr5TrYaDhKtxFkcdK0O2dKUqUAKY=; b=AiaVUiyjwspVxQWN/zO2yWIaGRxUSD74tK1dSirpU+ziUP98/mzDUE4T6yOAbhKvfO z+U5lOewED4Wq2h3dRXt7ydJvZllNLIUEqXv+Sj+PqMb/Pf1LgBOoty6G32GLBvICdu/ l2BwVk+UufA1ZHuEkTPuak1vl5fxUa0zMxXm3BQr1o0eDrEZsGRDuGSCVUA0gLTzC78R 1HUawnZrcG+gzFuMG3jUBbhnB4AXIzMjb/yHCPecdQo8RR2xrsLiTCS+CqhGoNy4I1ZY 1G05yjgsNjyaPsBfDwdSod3iO0rPxAzjby33VKPrKEt2CkwHeIcNIAwco4q3MrZovAZY dTrw== X-Gm-Message-State: AOAM533Cph5Im/L3mN82qARbHWM3gazpF2CEOYxjLNeC37ho1k/PWfSp U4iUH9KMZh0jfEho+FvfdcI= X-Google-Smtp-Source: ABdhPJz0qbFjLyXMAhWlltGK8rjKklwLlr9+2dkUYEbKgKgjvb7OPmRU1rKF7wCXQbHq0nsWxAFJew== X-Received: by 2002:a63:a16:: with SMTP id 22mr27343770pgk.345.1619625125372; Wed, 28 Apr 2021 08:52:05 -0700 (PDT) Received: from [192.168.3.219] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id k8sm132821pfk.189.2021.04.28.08.52.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 28 Apr 2021 08:52:04 -0700 (PDT) Subject: Re: [PATCH v2] block: Improve limiting the bio size To: Changheun Lee Cc: axboe@kernel.dk, bgoncalv@redhat.com, hch@lst.de, jaegeuk@kernel.org, linux-block@vger.kernel.org, ming.lei@redhat.com, yi.zhang@redhat.com References: <20210428072123.3155-1-nanich.lee@samsung.com> From: Bart Van Assche Message-ID: Date: Wed, 28 Apr 2021 08:52:03 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210428072123.3155-1-nanich.lee@samsung.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 4/28/21 12:21 AM, Changheun Lee wrote: > Actually I don't know why NULL pointer dereference is occurred with Bart's > patch in blk_rq_map_kern(). And same problem have not occured yet in my > test environment with Bart's patch. > Maybe I missed something, or missunderstood? The call trace that I shared on the linux-block mailing list was encountered inside a VM that has a SATA disk attached to it and also a SATA CD-ROM. Does replicating that setup allow to reproduce the NULL pointer dereference that I reported? Bart.