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Message-Id: <20240908102751.14188-1-aha310510@gmail.com>
Date: Sun, 8 Sep 2024 19:27:51 +0900
From: Jeongjun Park <aha310510@...il.com>
To: syzbot+702361cf7e3d95758761@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: KCSAN: data-race in generic_fillattr / shmem_mknod (2)
#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
---
fs/ext4/orphan.c | 2 +-
fs/ext4/super.c | 4 ++--
mm/percpu.c | 5 ++---
mm/shmem.c | 12 +++++++-----
4 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c
index e5b47dda3317..08299b2a1b3b 100644
--- a/fs/ext4/orphan.c
+++ b/fs/ext4/orphan.c
@@ -293,7 +293,7 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
mutex_unlock(&sbi->s_orphan_lock);
goto out_brelse;
}
- NEXT_ORPHAN(i_prev) = ino_next;
+ WRITE_ONCE(NEXT_ORPHAN(i_prev), ino_next);
err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
mutex_unlock(&sbi->s_orphan_lock);
}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e72145c4ae5a..8cc5e19bfe78 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -346,7 +346,7 @@ __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);
}
@@ -402,7 +402,7 @@ 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);
}
diff --git a/mm/percpu.c b/mm/percpu.c
index 20d91af8c033..5c958a54da51 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1864,7 +1864,6 @@ void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
area_found:
pcpu_stats_area_alloc(chunk, size);
- spin_unlock_irqrestore(&pcpu_lock, flags);
/* populate if not all pages are already there */
if (!is_atomic) {
@@ -1878,14 +1877,12 @@ void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
- spin_lock_irqsave(&pcpu_lock, flags);
if (ret) {
pcpu_free_area(chunk, off);
err = "failed to populate";
goto fail_unlock;
}
pcpu_chunk_populated(chunk, rs, re);
- spin_unlock_irqrestore(&pcpu_lock, flags);
}
mutex_unlock(&pcpu_alloc_mutex);
@@ -1894,6 +1891,8 @@ void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
pcpu_schedule_balance_work();
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+
/* clear the areas and return address relative to base address */
for_each_possible_cpu(cpu)
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
diff --git a/mm/shmem.c b/mm/shmem.c
index 5a77acf6ac6a..1595f6e7688c 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1154,7 +1154,9 @@ static int shmem_getattr(struct mnt_idmap *idmap,
stat->attributes_mask |= (STATX_ATTR_APPEND |
STATX_ATTR_IMMUTABLE |
STATX_ATTR_NODUMP);
+ inode_lock_shared(inode);
generic_fillattr(idmap, request_mask, inode, stat);
+ inode_unlock_shared(inode);
if (shmem_is_huge(inode, 0, false, NULL, 0))
stat->blksize = HPAGE_PMD_SIZE;
@@ -3439,7 +3441,7 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir,
if (error)
goto out_iput;
- dir->i_size += BOGO_DIRENT_SIZE;
+ i_size_write(dir, i_size_read(dir) + BOGO_DIRENT_SIZE);
inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
inode_inc_iversion(dir);
d_instantiate(dentry, inode);
@@ -3526,7 +3528,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir,
goto out;
}
- dir->i_size += BOGO_DIRENT_SIZE;
+ i_size_write(dir, i_size_read(dir) + BOGO_DIRENT_SIZE);
inode_set_mtime_to_ts(dir,
inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));
inode_inc_iversion(dir);
@@ -3639,8 +3641,8 @@ static int shmem_rename2(struct mnt_idmap *idmap,
inc_nlink(new_dir);
}
- old_dir->i_size -= BOGO_DIRENT_SIZE;
- new_dir->i_size += BOGO_DIRENT_SIZE;
+ i_size_write(old_dir, i_size_read(old_dir) - BOGO_DIRENT_SIZE);
+ i_size_write(new_dir, i_size_read(new_dir) + BOGO_DIRENT_SIZE);
simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
inode_inc_iversion(old_dir);
inode_inc_iversion(new_dir);
@@ -3694,7 +3696,7 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir,
folio_unlock(folio);
folio_put(folio);
}
- dir->i_size += BOGO_DIRENT_SIZE;
+ i_size_write(dir, i_size_read(dir) + BOGO_DIRENT_SIZE);
inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
inode_inc_iversion(dir);
d_instantiate(dentry, inode);
--
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