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=-2.5 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 AFAFAC43610 for ; Wed, 14 Nov 2018 15:18:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7911722506 for ; Wed, 14 Nov 2018 15:18:29 +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="K+Rxj7wP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7911722506 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732367AbeKOBWH (ORCPT ); Wed, 14 Nov 2018 20:22:07 -0500 Received: from mail-it1-f172.google.com ([209.85.166.172]:39283 "EHLO mail-it1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732485AbeKOBWH (ORCPT ); Wed, 14 Nov 2018 20:22:07 -0500 Received: by mail-it1-f172.google.com with SMTP id m15so24350356itl.4 for ; Wed, 14 Nov 2018 07:18:27 -0800 (PST) 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=HZ+inWvfHVDSEV1usxer1b2XqfBkS3568/ukX1pOf1M=; b=K+Rxj7wPrdTCWQLhNRupB4mTyIqSqc10IWF6H72K2rlgYNHwaXoJ3RfU2g+k3rfWQc mfhqUqLuQN+4haK7oPaFeYNHNfZPPQKSQrwmNTSeo8GJyK3J+HYbK/7CmaZ7yFCmeGDK Kkb9+Krywz7K2fkhgiiolbQjuMOkMqMQmtooAEjO7rLhj9s5azYXa9+sV+tt9hpoUlEd NgH3C9P311UP9DW5RIUq6uCCbNgjFeZKwmAKiuTnrci7kd1w969zVJETOfHs0YYbg3R+ 6zO7398g+/bahknIK9nsPD40HAqkax2Yt3+/8Ad0fR0V7X4hxCWB2AvLTwZICvfv6NT7 mnvw== 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=HZ+inWvfHVDSEV1usxer1b2XqfBkS3568/ukX1pOf1M=; b=XsXmBC2Fr6fMn1+VedOCZkkqVoT3EXlLsi6jnGj4KNfphqsdfx29gukiYExpjyjLzb udr2ay7aXu+JBj908SEJmoR5sOv/rIyJakrvIL/4uqCeQ0b9mFbaJBWT40ws88p8ILAK SfEfy20vkZ+Krf2pwHSfE5FAWW/0IBZT5q/dExCSCqETFOIie1lleJ7wAIvh9kdbbj/l khGmpz7W1S3gw6D7vnxz4dTptua1GnOt4qqvbKYDkeGvq25cNkVUxeZWYBH1agISMLj5 XB1gxmhzQ9Luy1vT1D+11KaiBqwIUjrGdySyBzfnDT3n+SF6yOIkTSUkssHYl5YPNc6C 53eg== X-Gm-Message-State: AGRZ1gJFUz354J71UjgwfjSb7vDr613wsObF0p6jyWuf3riGKyGMipma dV+ZKpExTrl2F/4JeOJCx3hL2Q== X-Google-Smtp-Source: AJdET5dnEpQ25v6+ETv7+Ja7eR+2EZc0UfDq5s3KBL1Z2E46gqjmwVnlKivPy/ezagMmUUgchymkjw== X-Received: by 2002:a24:1706:: with SMTP id 6-v6mr2279539ith.169.1542208707074; Wed, 14 Nov 2018 07:18:27 -0800 (PST) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id c102sm2653599itd.38.2018.11.14.07.18.25 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Nov 2018 07:18:25 -0800 (PST) Subject: Re: [PATCH] block: fix 32 bit overflow in __blkdev_issue_discard() To: Dave Chinner , linux-xfs@vger.kernel.org Cc: linux-block@vger.kernel.org, Ming Lei References: <20181113214337.20581-1-david@fromorbit.com> From: Jens Axboe Message-ID: <10a8dd78-7c00-8593-9f4e-b20eb1161b92@kernel.dk> Date: Wed, 14 Nov 2018 08:18:24 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181113214337.20581-1-david@fromorbit.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 11/13/18 2:43 PM, Dave Chinner wrote: > From: Dave Chinner > > A discard cleanup merged into 4.20-rc2 causes fstests xfs/259 to > fall into an endless loop in the discard code. The test is creating > a device that is exactly 2^32 sectors in size to test mkfs boundary > conditions around the 32 bit sector overflow region. > > mkfs issues a discard for the entire device size by default, and > hence this throws a sector count of 2^32 into > blkdev_issue_discard(). It takes the number of sectors to discard as > a sector_t - a 64 bit value. > > The commit ba5d73851e71 ("block: cleanup __blkdev_issue_discard") > takes this sector count and casts it to a 32 bit value before > comapring it against the maximum allowed discard size the device > has. This truncates away the upper 32 bits, and so if the lower 32 > bits of the sector count is zero, it starts issuing discards of > length 0. This causes the code to fall into an endless loop, issuing > a zero length discards over and over again on the same sector. Applied, thanks. Ming, can you please add a blktests test for this case? This is the 2nd time it's been broken. -- Jens Axboe