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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 210E6C433E0 for ; Sat, 20 Jun 2020 17:14:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E67F124051 for ; Sat, 20 Jun 2020 17:14:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TD91KHoC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727866AbgFTROB (ORCPT ); Sat, 20 Jun 2020 13:14:01 -0400 Received: from mail-pj1-f67.google.com ([209.85.216.67]:50727 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725290AbgFTROB (ORCPT ); Sat, 20 Jun 2020 13:14:01 -0400 Received: by mail-pj1-f67.google.com with SMTP id jz3so5737894pjb.0 for ; Sat, 20 Jun 2020 10:14:00 -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:references:mime-version :content-disposition:in-reply-to; bh=dsIbqeFSwV25KAPM0sIkenvbQAR8H9io+QwasfROH0Q=; b=TD91KHoC78IoyMTdN9mn9dEj1O0j8WSi7EVqZyrQ1xC0k/AuGz63uiY6CIWoYB510v zLwjZ6PjpwmT8ZWj0AwF67yErThjQVRhFd9uUHBI3yRy990SDDkX1vwZu2ERyDZ/hg/O R8jr/whbDaWx1do88FkJt7Dy7Vh5X4t1ut159heDIqi3mS9CjN63nddKMagknVnQTOtW r4WL5KJjXOugxHONFyWXxD8Eh9hh3yNfv9DrE0l7N1/w1QGXy9347NdKxPInG6BzPaai /KgjspEOY6lN8gURGl+MXvFSxsXFNr3Cyq5CF3a8cq5e+ZVOQJc+8m2LxWLT8pX/QvF7 3V0g== 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:references :mime-version:content-disposition:in-reply-to; bh=dsIbqeFSwV25KAPM0sIkenvbQAR8H9io+QwasfROH0Q=; b=L7qkSRVL8WU47OglGHfV1KdNrSETac78RDXaUqeWvBL/kbjpQneQuYEWoGS4rYpR2c dvlye4M6G+5PgjMB2ANkRQvMb3GIfA8fyOw93rzpUvdgRP6N7xANL0eELvIb7UaZGETT tltYeNDsTaVVD2SaPm+90CiJ+ZSovSMueEvhDXRTIj4xetZSpf3KG6N0V3Fwqmz99RkD yerEh98hB07gboBpldj4hhStNu/7VPLI1Ei75LK8Cw0ef4rUX4Gk6bWLLinsxColF2ft 5V6wx9lenTmqTLYUruq/Jb8woK4RFO6Fe8LNEgeeSnw4xoiKZdvbbEY0OYaNdhIrjgkb T8/w== X-Gm-Message-State: AOAM531KRqpgFYdzAGomPHalXAysWWrK8J1RrIIpv48+tiXTUmfCMN+J XUulD20/IUMbND1j5OwTkFk= X-Google-Smtp-Source: ABdhPJy8IX0ER9nYA60qDM5fFoxwpIy/sZ+galAxD2WD5yf2HU0TDyyGK9eHwD50Wwoy26t/FZYSkQ== X-Received: by 2002:a17:90a:3749:: with SMTP id u67mr9113668pjb.129.1592673179708; Sat, 20 Jun 2020 10:12:59 -0700 (PDT) Received: from localhost ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id p186sm9292565pfg.107.2020.06.20.10.12.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Jun 2020 10:12:59 -0700 (PDT) Date: Sun, 21 Jun 2020 01:12:51 +0800 From: Murphy Zhou To: Amir Goldstein Cc: Murphy Zhou , Miklos Szeredi , overlayfs , Chengguang Xu , Miklos Szeredi Subject: Re: [PATCH v2] ovl: fix NULL ref while cleanup index when mount with nfs_export Message-ID: <20200620171251.2rl2fwnsyazj4dz7@xzhoux.usersys.redhat.com> References: <20200620132845.w34h6y2p5txrsd73@xzhoux.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-unionfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Sat, Jun 20, 2020 at 07:14:02PM +0300, Amir Goldstein wrote: > On Sat, Jun 20, 2020 at 4:28 PM Murphy Zhou wrote: > > > > Mounting with nfs_export=on, xfstests overlay/031 triggers panic > > since v5.8-rc1 overlayfs updates. > > > > [ 7492.110430] run fstests overlay/031 at 2020-06-10 00:25:16 > > [ 7492.487300] overlayfs: disabling metacopy due to nfs_export=on > > [ 7492.514270] overlayfs: "xino=on" is useless with all layers on same fs, ignore. > > [ 7492.648049] overlayfs: disabling metacopy due to nfs_export=on > > [ 7492.675189] overlayfs: "xino=on" is useless with all layers on same fs, ignore. > > [ 7492.781437] overlayfs: disabling metacopy due to nfs_export=on > > [ 7492.808608] overlayfs: "xino=on" is useless with all layers on same fs, ignore. > > [ 7492.842132] overlayfs: orphan index entry (index/00fb1d000175e1f1e51e134b75b98d1f572f21252d030004002ae1559a, ftype=4000, nlink=2) > > [ 7492.895298] BUG: kernel NULL pointer dereference, address: 0000000000000030 > > [ 7492.926984] #PF: supervisor read access in kernel mode > > [ 7492.950703] #PF: error_code(0x0000) - not-present page > > [ 7492.974243] PGD 0 P4D 0 > > [ 7492.985754] Oops: 0000 [#1] SMP PTI > > [ 7493.001771] CPU: 11 PID: 951781 Comm: mount Not tainted 5.7.0+ #1 > > [ 7493.029799] Hardware name: HP ProLiant DL388p Gen8, BIOS P70 09/18/2013 > > [ 7493.059809] RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay] > > [ 7493.087978] Code: 00 00 0f 1f 44 00 00 41 57 41 56 49 89 f6 41 55 41 54 49 89 d4 55 48 89 fd 53 48 83 ec 08 4c 8b 47 20 48 83 bf a8 00 00 00 00 <4d> 8b 68 30 0f 84 41 01 00 00 80 7d 7c 00 0f 85 b7 00 00 00 48 8b > > [ 7493.173542] RSP: 0018:ffffbb8409a7fc20 EFLAGS: 00010246 > > [ 7493.197332] RAX: 00000000fffffffe RBX: ffff9425aa44ee40 RCX: 0000000000000000 > > [ 7493.230058] RDX: ffff9420f64c5a40 RSI: ffff9425a25d91c8 RDI: ffff94259dfc9680 > > [ 7493.262699] RBP: ffff94259dfc9680 R08: 0000000000000000 R09: 000000000000000b > > [ 7493.295568] R10: 0000000000000000 R11: ffffbb8409a7fab8 R12: ffff9420f64c5a40 > > [ 7493.328117] R13: ffff94259dfc9680 R14: ffff9425a25d91c8 R15: ffff9420f64c5a40 > > [ 7493.360681] FS: 00007f43bdfc2080(0000) GS:ffff9425af740000(0000) knlGS:0000000000000000 > > [ 7493.397797] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 7493.424340] CR2: 0000000000000030 CR3: 000000082bd18001 CR4: 00000000001606e0 > > [ 7493.456765] Call Trace: > > [ 7493.467695] ovl_indexdir_cleanup+0x1ab/0x330 [overlay] > > [ 7493.491605] ? ovl_cache_entry_find_link.constprop.18+0x80/0x80 [overlay] > > [ 7493.522754] ovl_fill_super+0x1031/0x11d0 [overlay] > > [ 7493.545183] ? sget+0x1c7/0x220 > > [ 7493.559242] ? get_anon_bdev+0x40/0x40 > > [ 7493.576593] ? ovl_show_options+0x230/0x230 [overlay] > > [ 7493.599407] mount_nodev+0x48/0xa0 > > [ 7493.615187] legacy_get_tree+0x27/0x40 > > [ 7493.632193] vfs_get_tree+0x25/0xb0 > > [ 7493.647926] do_mount+0x7ae/0x9d0 > > [ 7493.662996] ? _copy_from_user+0x2c/0x60 > > [ 7493.681534] __x64_sys_mount+0xc4/0xe0 > > [ 7493.698370] do_syscall_64+0x55/0x1b0 > > [ 7493.715177] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > [ 7493.737697] RIP: 0033:0x7f43bcffec8e > > [ 7493.753986] Code: Bad RIP value. > > [ 7493.768721] RSP: 002b:00007ffe1b7c74f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > > [ 7493.803468] RAX: ffffffffffffffda RBX: 000055ba081c1310 RCX: 00007f43bcffec8e > > [ 7493.837362] RDX: 000055ba081c1a00 RSI: 000055ba081c1a40 RDI: 000055ba081c1a20 > > [ 7493.872745] RBP: 00007f43bdda9184 R08: 000055ba081c1880 R09: 0000000000000003 > > [ 7493.905227] R10: 00000000c0ed0000 R11: 0000000000000246 R12: 0000000000000000 > > [ 7493.938152] R13: 00000000c0ed0000 R14: 000055ba081c1a20 R15: 000055ba081c1a00 > > > > Bisect says the first bad commit is: > > [c21c839b8448dd4b1e37ffc1bde928f57d34c0db] ovl: whiteout inode sharing > > > > Minimal reproducer: > > -------------------------------------------------- > > rm -rf l u w m > > mkdir -p l u w m > > mkdir -p l/testdir > > touch l/testdir/testfile > > mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m > > echo 1 > m/testdir/testfile > > umount m > > rm -rf u/testdir > > mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m > > umount m > > -------------------------------------------------- > > > > When mount with nfs_export=on, and fail to verify an orphan index, we're > > cleaning this index from indexdir by calling ovl_cleanup_and_whiteout, > > in which we should clean indexdir rather than workdir. We start to use > > ofs structure and only clean workdir since commit c21c839b8448 > > ("ovl: whiteout inode sharing"), breaking the nfs_export code path. > > > > Fixing this by passing additional explicit workdir argument to the cleanup > > helper and passing indexdir as workdir argument in ovl_indexdir_cleanup and > > ovl_cleanup_index. > > > > Suggested-by: Amir Goldstein > > Signed-off-by: Murphy Zhou > > --- > > v2: > > Pass workdir as argument along with ofs to the helper instead of > > checking availability of the dirs. > > Pass indexdir in ovl_indexdir_cleanup and ovl_cleanup_index. > > Sorry for not looking closer before, I wasn't near my workstation. > Here is another suggestion. > I think Miklos will like this one better, because he was the one who removed > the workdir from Chengguang's original patch. > > The design was that ovl->workdir will point at ovl->indexdir, but we did > it too late for ovl_indexdir_cleanup(). > No reason not to do it sooner, because once we get success from > ofs->indexdir = ovl_workdir_create(... there is no turning back. hmm.. this is smarter. > > Feel free to re-post this with proper commit message after testing and > verifying that moving the code didn't break any other error path. It's your patch :) I'll test and report back. You post it. Thanks! > > Thanks, > Amir. > From 4e04457a1b616cc84331214017014bebd479461a Mon Sep 17 00:00:00 2001 > From: Amir Goldstein > Date: Sat, 20 Jun 2020 19:04:35 +0300 > Subject: [PATCH] ovl: fix NULL ref while cleanup index when mount with > nfs_export > > ... > > Fixes: commit c21c839b8448 ("ovl: whiteout inode sharing") > Signed-off-by: Amir Goldstein > --- > fs/overlayfs/super.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index 91476bc422f9..15939ab39c1c 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -1354,6 +1354,12 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, > > ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); > if (ofs->indexdir) { > + /* index dir will act also as workdir */ > + iput(ofs->workdir_trap); > + ofs->workdir_trap = NULL; > + dput(ofs->workdir); > + ofs->workdir = dget(ofs->indexdir); > + > err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, > "indexdir"); > if (err) > @@ -1843,20 +1849,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) > sb->s_flags |= SB_RDONLY; > > if (!(ovl_force_readonly(ofs)) && ofs->config.index) { > - /* index dir will act also as workdir */ > - dput(ofs->workdir); > - ofs->workdir = NULL; > - iput(ofs->workdir_trap); > - ofs->workdir_trap = NULL; > - > err = ovl_get_indexdir(sb, ofs, oe, &upperpath); > if (err) > goto out_free_oe; > > /* Force r/o mount with no index dir */ > - if (ofs->indexdir) > - ofs->workdir = dget(ofs->indexdir); > - else > + if (!ofs->indexdir) > sb->s_flags |= SB_RDONLY; > } > > -- > 2.17.1 > -- Murphy