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| author | Theodore Ts'o <tytso@mit.edu> | 2023-05-06 04:02:30 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-05-14 01:05:05 +0300 |
| commit | a44be64bbecb15a452496f60db6eacfee2b59c79 (patch) | |
| tree | 9e63d1c90c97a5f1209687f07415978c9da7835f | |
| parent | fa83c34e3e56b3c672af38059e066242655271b1 (diff) | |
| download | linux-a44be64bbecb15a452496f60db6eacfee2b59c79.tar.xz | |
ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled
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>
| -rw-r--r-- | fs/ext4/super.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 425b95a7a0ab..c7bc4a2709cc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6387,6 +6387,7 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) 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; @@ -6573,7 +6574,7 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) 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)); @@ -6632,6 +6633,9 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) 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); |