From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 808FB171A1 for ; Mon, 22 May 2023 19:14:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BF0AC433EF; Mon, 22 May 2023 19:14:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684782894; bh=FVGeJdPlv4hjJDz3BId893dBH5exQXoy0bO+inVEjGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t9RPKMccxtx0zWDfWSpvG17iuIxYFgR9aeOBAaZd4em/H2Hu2Gb4MSpLKzsEpECJ1 6g+PfbGZ+aolCIXfShyZkI0lBXvgBA/8yLogu2DIUGifo5B5on52bNQDfCD2h5C8Z8 0nIfxLF0tgPg6xg6ccElB6CNJYk4oQQD9YkLpMqQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, syzbot+6385d7d3065524c5ca6d@syzkaller.appspotmail.com, Theodore Tso , Sasha Levin Subject: [PATCH 5.15 026/203] ext4: dont clear SB_RDONLY when remounting r/w until quota is re-enabled Date: Mon, 22 May 2023 20:07:30 +0100 Message-Id: <20230522190355.686982119@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190354.935300867@linuxfoundation.org> References: <20230522190354.935300867@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Theodore Ts'o [ Upstream commit a44be64bbecb15a452496f60db6eacfee2b59c79 ] When a file system currently mounted read/only is remounted read/write, if we clear the SB_RDONLY flag too early, before the quota is initialized, and there is another process/thread constantly attempting to create a directory, it's possible to trigger the WARN_ON_ONCE(dquot_initialize_needed(inode)); in ext4_xattr_block_set(), with the following stack trace: WARNING: CPU: 0 PID: 5338 at fs/ext4/xattr.c:2141 ext4_xattr_block_set+0x2ef2/0x3680 RIP: 0010:ext4_xattr_block_set+0x2ef2/0x3680 fs/ext4/xattr.c:2141 Call Trace: ext4_xattr_set_handle+0xcd4/0x15c0 fs/ext4/xattr.c:2458 ext4_initxattrs+0xa3/0x110 fs/ext4/xattr_security.c:44 security_inode_init_security+0x2df/0x3f0 security/security.c:1147 __ext4_new_inode+0x347e/0x43d0 fs/ext4/ialloc.c:1324 ext4_mkdir+0x425/0xce0 fs/ext4/namei.c:2992 vfs_mkdir+0x29d/0x450 fs/namei.c:4038 do_mkdirat+0x264/0x520 fs/namei.c:4061 __do_sys_mkdirat fs/namei.c:4076 [inline] __se_sys_mkdirat fs/namei.c:4074 [inline] __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4074 Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230506142419.984260-1-tytso@mit.edu Reported-by: syzbot+6385d7d3065524c5ca6d@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=6513f6cb5cd6b5fc9f37e3bb70d273b94be9c34c Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/super.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index d062bad1384be..c527ec2b041fb 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5746,6 +5746,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) struct ext4_mount_options old_opts; ext4_group_t g; int err = 0; + int enable_rw = 0; #ifdef CONFIG_QUOTA int enable_quota = 0; int i, j; @@ -5946,7 +5947,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) if (err) goto restore_opts; - sb->s_flags &= ~SB_RDONLY; + enable_rw = 1; if (ext4_has_feature_mmp(sb)) { err = ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)); @@ -6005,6 +6006,9 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks) ext4_release_system_zone(sb); + if (enable_rw) + sb->s_flags &= ~SB_RDONLY; + if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb)) ext4_stop_mmpd(sbi); -- 2.39.2