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=-8.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A9D2BC2D0A8 for ; Sat, 26 Sep 2020 04:19:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DACD207C4 for ; Sat, 26 Sep 2020 04:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601093943; bh=AJxwQo/L+ID93H6tPKPieFQbSPWKO3Vas2ik0yvPZ+s=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=k8MEdVSoH3xpKvsdn4VMHSF6D1Xm2q3KBlOd9rCkiPWgtCdrZ98YvgFsUmKIhKwSZ XnY74n7bL5qBK+7iJsZ6W2TxMBTrXHt+PZ7e9nUtSrJ2K9B5rF2V3UcghqSnhCgjW3 v0sxPJF93kHcT+Fe+4r8mqRRWpXh2hSFYM9wtRdM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730038AbgIZETD (ORCPT ); Sat, 26 Sep 2020 00:19:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:51592 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730033AbgIZETD (ORCPT ); Sat, 26 Sep 2020 00:19:03 -0400 Received: from localhost.localdomain (c-71-198-47-131.hsd1.ca.comcast.net [71.198.47.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 136A02076D; Sat, 26 Sep 2020 04:19:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601093942; bh=AJxwQo/L+ID93H6tPKPieFQbSPWKO3Vas2ik0yvPZ+s=; h=Date:From:To:Subject:In-Reply-To:From; b=Zed3OG/wK9qxn9wnbcZ9fmAs2DU7YwezSNB6Y9AsXjQzhtgMbre9rzAVd6MzH7LQd UFtvvFvKJKbQ44+3YsTtarIH+cCOiJ9Ak0aCVJDBRw5pg9eNFrFcJUK5XyPPJXWmos 6v5fAzaCzSye+xx718QJRjHbtkRgmoCJyqRZbB/g= Date: Fri, 25 Sep 2020 21:19:01 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aquini@redhat.com, cmaiolino@redhat.com, david@fromorbit.com, esandeen@redhat.com, hsiangkao@redhat.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, shy828301@gmail.com, stable@vger.kernel.org, torvalds@linux-foundation.org, willy@infradead.org, ying.huang@intel.com Subject: [patch 1/9] mm, THP, swap: fix allocating cluster for swapfile by mistake Message-ID: <20200926041901.P-A_BQZ2V%akpm@linux-foundation.org> In-Reply-To: <20200925211725.0fea54be9e9715486efea21f@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Gao Xiang Subject: mm, THP, swap: fix allocating cluster for swapfile by mistake SWP_FS is used to make swap_{read,write}page() go through the filesystem, and it's only used for swap files over NFS. So, !SWP_FS means non NFS for now, it could be either file backed or device backed. Something similar goes with legacy SWP_FILE. So in order to achieve the goal of the original patch, SWP_BLKDEV should be used instead. FS corruption can be observed with SSD device + XFS + fragmented swapfile due to CONFIG_THP_SWAP=y. I reproduced the issue with the following details: Environment: QEMU + upstream kernel + buildroot + NVMe (2 GB) Kernel config: CONFIG_BLK_DEV_NVME=y CONFIG_THP_SWAP=y Some reproducable steps: mkfs.xfs -f /dev/nvme0n1 mkdir /tmp/mnt mount /dev/nvme0n1 /tmp/mnt bs="32k" sz="1024m" # doesn't matter too much, I also tried 16m xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw xfs_io -f -c "pwrite -F -S 0 -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fsync" /tmp/mnt/sw mkswap /tmp/mnt/sw swapon /tmp/mnt/sw stress --vm 2 --vm-bytes 600M # doesn't matter too much as well Symptoms: - FS corruption (e.g. checksum failure) - memory corruption at: 0xd2808010 - segfault Link: https://lkml.kernel.org/r/20200820045323.7809-1-hsiangkao@redhat.com Fixes: f0eea189e8e9 ("mm, THP, swap: Don't allocate huge cluster for file backed swap device") Fixes: 38d8b4e6bdc8 ("mm, THP, swap: delay splitting THP during swap out") Signed-off-by: Gao Xiang Reviewed-by: "Huang, Ying" Reviewed-by: Yang Shi Acked-by: Rafael Aquini Cc: Matthew Wilcox Cc: Carlos Maiolino Cc: Eric Sandeen Cc: Dave Chinner Cc: Signed-off-by: Andrew Morton --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/swapfile.c~mm-thp-swap-fix-allocating-cluster-for-swapfile-by-mistake +++ a/mm/swapfile.c @@ -1078,7 +1078,7 @@ start_over: goto nextsi; } if (size == SWAPFILE_CLUSTER) { - if (!(si->flags & SWP_FS)) + if (si->flags & SWP_BLKDEV) n_ret = swap_alloc_cluster(si, swp_entries); } else n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE, _