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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 E6CCDC433E0 for ; Thu, 18 Mar 2021 18:17:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B50D64F24 for ; Thu, 18 Mar 2021 18:17:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232443AbhCRSQq (ORCPT ); Thu, 18 Mar 2021 14:16:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232560AbhCRSQQ (ORCPT ); Thu, 18 Mar 2021 14:16:16 -0400 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40509C06174A for ; Thu, 18 Mar 2021 11:16:16 -0700 (PDT) Received: by mail-qt1-x835.google.com with SMTP id 94so4829596qtc.0 for ; Thu, 18 Mar 2021 11:16:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=Z5JvJi+HTjCGsE7ucXOoCnR2oyC4fJqRuW05biMaRZg=; b=GnGHsls6FcTIVkyudqfwul4XqEW+otcbyxbYr1PXg/jQE77zQlXmE/bKqrjlyUpRiv sVAHU/H1GR1QOqtYR7O2T7MoEPJqns6T6537WXmuSJajXpothh6fTkmdM1qcOcJA4kJ9 +R1HFEcSxnHaBjObWwGrikrzc3B1lcJ+qPuoLJq456qPD124nfE+eT+HhGVZVsqLH9j2 lWtCmM0USTLozSj2WZhbJu+1ZdZzYuZCQpQHPMGpzRGiQKiLQlokZwuYFyzdh+ezUIGT R0uAq3MINUzfc6tN7x+1PfG64jns6ZaxzAgQuXv4OKxq0mEClDT7+H6hwkx5iKUjr5mN l3Kw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=Z5JvJi+HTjCGsE7ucXOoCnR2oyC4fJqRuW05biMaRZg=; b=jnuz8vgh+iZps4g6+1DhY56IGaXoS8zFmH4d5h4kfVrK2C3C6zEaB8KBdRbmKBqlA7 Bw/MRqO6k9/rWpK/FcVhUvcddfBnsqKwrh8uqUDWsWtGQ6ac0nzPwkZ+NlyrS3F63Or1 7+AJdF9OG2jIE5S0njbqRV4YtXqWtKCAkpZYZ/qnoVdmr5k0stKUUQveJwwUDCenAWlp FvkuMuimPVfhbzByijh+4UpnFkFsLTjfiCVMFhOvfJ5z73j2bwnj/Mcg5h/S1ag8KUDG xpluLyp57CTXA4stdbu7FBaJ9SiJBk2wvyT+hXf00EHJzvRKEeQpHGsCnab1EGr8xdD+ DHyg== X-Gm-Message-State: AOAM533qOUdT4tYFWOAEfWxkhD5CFnMznuRlOr2JNEikUY8w2FaYNAjk AQqMEiXiORPOGQQx6DgQJsm3A9OOhvU= X-Google-Smtp-Source: ABdhPJyYKXBF9UIsSlEH25YBfgn0IsU1o8lW3ONDVe2vQsgNKTRTxFy0nwfx8B+a3hodKxSA9+ot6g== X-Received: by 2002:aed:20cd:: with SMTP id 71mr5072985qtb.346.1616091375344; Thu, 18 Mar 2021 11:16:15 -0700 (PDT) Received: from localhost.localdomain (c-73-60-226-25.hsd1.nh.comcast.net. [73.60.226.25]) by smtp.gmail.com with ESMTPSA id i9sm2349320qko.69.2021.03.18.11.16.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 11:16:15 -0700 (PDT) Date: Thu, 18 Mar 2021 14:16:13 -0400 From: Eric Whitney To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, willy@infradead.org Subject: generic/418 regression seen on 5.12-rc3 Message-ID: <20210318181613.GA13891@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org As mentioned in today's ext4 concall, I've seen generic/418 fail from time to time when run on 5.12-rc3 and 5.12-rc1 kernels. This first occurred when running the 1k test case using kvm-xfstests. I was then able to bisect the failure to a patch landed in the -rc1 merge window: (bd8a1f3655a7) mm/filemap: support readpage splitting a page Typical test output resulting from a failure looks like: QA output created by 418 +cmpbuf: offset 0: Expected: 0x1, got 0x0 +[6:0] FAIL - comparison failed, offset 3072 +diotest -w -b 512 -n 8 -i 4 failed at loop 0 Silence is golden ... I've also been able to reproduce the failure on -rc3 in the 4k test case as well. The failure frequency there was 10 out of 100 runs. It was anywhere from 2 to 8 failures out of 100 runs in the 1k case. So, the failure isn't dependent upon block size less than page size. Eric