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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 55D53C433E2 for ; Sun, 12 Jul 2020 20:37:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3675920702 for ; Sun, 12 Jul 2020 20:37:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="OKbsTsBj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729410AbgGLUhW (ORCPT ); Sun, 12 Jul 2020 16:37:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729287AbgGLUhV (ORCPT ); Sun, 12 Jul 2020 16:37:21 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4D50C061794 for ; Sun, 12 Jul 2020 13:37:21 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id q17so4543008pls.9 for ; Sun, 12 Jul 2020 13:37:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=/nuEi5LSAR+BLYQ3M1VbbdXftovzZ8g7a0HCozi5Z14=; b=OKbsTsBjFpc2Q2RpjNItVv+FVfQd9DdK31sK2+p3JNMHwt1q+he7+lWvU0dJ6lQ5pY FyNrVK7DBeU3wgSpTq+PpurW0LFMIq2FaqSUR73fvsSD+VUlCF4F67yomf7csOm33DY2 FilVSTqU5S6LDR5+1jOn1PUXuHjaw/28YUtIx4tkeFUFttTgv7jHUpsTjfq5KU4EZ6Z+ JtVlGLVNSkS4vpVdGQ+0jSfP3Rm8y1TZLF7Pmph2+YGjy+udBCGPJBxgr4/h0P2LO3dA Ut1qM++ITGMc5j5d8XgFpmlQMPqXnzcKap1Sp+3WWXF4nzT84Y18CdJWB0Rk5m/d2vm4 CtEw== 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=/nuEi5LSAR+BLYQ3M1VbbdXftovzZ8g7a0HCozi5Z14=; b=HZ/h092puCEGj1SzNVFhF0gJaXWzBow60Nme7THCCBYrm9iQrvRpFUkyRy32pK33Nb 0SwJ8QkTkWS9KAfm9tuJhCeIaztZztnxZ63+tzhwfjLcGc016IkXoLpphybYW/xzBGu6 XFT6uW4Jy2rDrPe5WVSFfI1ZUqEd+kRh9VqfuI/IYMYA2xIrrq+GLgSV4o9r0ybtb8bU /P+LAoElNgLlguanYEBuM48ObQDNkjjg53uHl/JjPLXuGOTmdvXh0aUdEKquUTJNEqMt 4F2Ro73581hEt+1J4HXhaHMuzqVtM36j/OcW+akYRFqrmIMpK5g5VCon/f2X+61/gz7T 3haw== X-Gm-Message-State: AOAM531CrSQgRac2kXYmTUmlHenxkd1qi5AdJzlKJzxP0w7UvLSrojrv xEOCH5P6MtafK1aEuY0z9GX5xQ== X-Google-Smtp-Source: ABdhPJxJ5S6nNjHYOWkL5qX+tcJMU4wE4qGu4a14gg3IesW7UiP86NpYK+fA596DOp1xGeR1N986aQ== X-Received: by 2002:a17:902:446:: with SMTP id 64mr23802034ple.157.1594586241283; Sun, 12 Jul 2020 13:37:21 -0700 (PDT) Received: from [192.168.1.182] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id nl5sm13018985pjb.36.2020.07.12.13.37.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 12 Jul 2020 13:37:20 -0700 (PDT) Subject: Re: [PATCH 1/2] bcache: avoid nr_stripes overflow in bcache_device_init() To: Coly Li , linux-bcache@vger.kernel.org Cc: linux-block@vger.kernel.org, Ken Raeburn , stable@vger.kernel.org References: <20200712174736.9840-1-colyli@suse.de> From: Jens Axboe Message-ID: <010a5d09-5de8-8f1e-4ff5-3f194f899073@kernel.dk> Date: Sun, 12 Jul 2020 14:37:19 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200712174736.9840-1-colyli@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-bcache-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On 7/12/20 11:47 AM, Coly Li wrote: > For some block devices which large capacity (e.g. 8TB) but small io_opt > size (e.g. 8 sectors), in bcache_device_init() the stripes number calcu- > lated by, > DIV_ROUND_UP_ULL(sectors, d->stripe_size); > might be overflow to the unsigned int bcache_device->nr_stripes. > > This patch uses an unsigned long variable to store DIV_ROUND_UP_ULL() > and after the value is checked to be available in unsigned int range, > sets it to bache_device->nr_stripes. Then the overflow is avoided. Does that work on 32-bit, where sizeof(unsigned long) == 4? -- Jens Axboe