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| author | Jeongjun Park <aha310510@gmail.com> | 2024-10-03 14:53:37 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2024-10-30 22:42:44 +0100 |
| commit | 902cc179c931a033cd7f4242353aa2733bf8524c (patch) | |
| tree | 9bdec08393329f0b1cf37ad822bda7a79e07a61b /fs/ext4 | |
| parent | ext4: Call ext4_journal_stop(handle) only once in ext4_dio_write_iter() (diff) | |
| download | linux-902cc179c931a033cd7f4242353aa2733bf8524c.tar.xz linux-902cc179c931a033cd7f4242353aa2733bf8524c.zip | |
ext4: supress data-race warnings in ext4_free_inodes_{count,set}()
find_group_other() and find_group_orlov() read *_lo, *_hi with
ext4_free_inodes_count without additional locking. This can cause
data-race warning, but since the lock is held for most writes and free
inodes value is generally not a problem even if it is incorrect, it is
more appropriate to use READ_ONCE()/WRITE_ONCE() than to add locking.
==================================================================
BUG: KCSAN: data-race in ext4_free_inodes_count / ext4_free_inodes_set
write to 0xffff88810404300e of 2 bytes by task 6254 on cpu 1:
ext4_free_inodes_set+0x1f/0x80 fs/ext4/super.c:405
__ext4_new_inode+0x15ca/0x2200 fs/ext4/ialloc.c:1216
ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391
vfs_symlink+0xca/0x1d0 fs/namei.c:4615
do_symlinkat+0xe3/0x340 fs/namei.c:4641
__do_sys_symlinkat fs/namei.c:4657 [inline]
__se_sys_symlinkat fs/namei.c:4654 [inline]
__x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654
x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
read to 0xffff88810404300e of 2 bytes by task 6257 on cpu 0:
ext4_free_inodes_count+0x1c/0x80 fs/ext4/super.c:349
find_group_other fs/ext4/ialloc.c:594 [inline]
__ext4_new_inode+0x6ec/0x2200 fs/ext4/ialloc.c:1017
ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391
vfs_symlink+0xca/0x1d0 fs/namei.c:4615
do_symlinkat+0xe3/0x340 fs/namei.c:4641
__do_sys_symlinkat fs/namei.c:4657 [inline]
__se_sys_symlinkat fs/namei.c:4654 [inline]
__x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654
x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Cc: stable@vger.kernel.org
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://patch.msgid.link/20241003125337.47283-1-aha310510@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/super.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 16a4ce704460..8337c4999f90 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -346,9 +346,9 @@ __u32 ext4_free_group_clusters(struct super_block *sb, __u32 ext4_free_inodes_count(struct super_block *sb, struct ext4_group_desc *bg) { - return le16_to_cpu(bg->bg_free_inodes_count_lo) | + return le16_to_cpu(READ_ONCE(bg->bg_free_inodes_count_lo)) | (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ? - (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0); + (__u32)le16_to_cpu(READ_ONCE(bg->bg_free_inodes_count_hi)) << 16 : 0); } __u32 ext4_used_dirs_count(struct super_block *sb, @@ -402,9 +402,9 @@ void ext4_free_group_clusters_set(struct super_block *sb, void ext4_free_inodes_set(struct super_block *sb, struct ext4_group_desc *bg, __u32 count) { - bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count); + WRITE_ONCE(bg->bg_free_inodes_count_lo, cpu_to_le16((__u16)count)); if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT) - bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16); + WRITE_ONCE(bg->bg_free_inodes_count_hi, cpu_to_le16(count >> 16)); } void ext4_used_dirs_set(struct super_block *sb, |