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ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled
[ Upstream commit a44be64bbe
]
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 <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
3f937d6615
commit
c53936d9fb
1 changed files with 5 additions and 1 deletions
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@ -5746,6 +5746,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
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struct ext4_mount_options old_opts;
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ext4_group_t g;
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int err = 0;
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int enable_rw = 0;
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#ifdef CONFIG_QUOTA
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int enable_quota = 0;
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int i, j;
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@ -5946,7 +5947,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
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if (err)
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goto restore_opts;
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sb->s_flags &= ~SB_RDONLY;
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enable_rw = 1;
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if (ext4_has_feature_mmp(sb)) {
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err = ext4_multi_mount_protect(sb,
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le64_to_cpu(es->s_mmp_block));
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@ -6005,6 +6006,9 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
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if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
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ext4_release_system_zone(sb);
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if (enable_rw)
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sb->s_flags &= ~SB_RDONLY;
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if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb))
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ext4_stop_mmpd(sbi);
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