static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
{
	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
	struct f2fs_nm_info *nm_i = NM_I(sbi);
	unsigned int nat_bits_bytes = nm_i->nat_blocks / BITS_PER_BYTE;
	unsigned int i;
	__u64 cp_ver = cur_cp_version(ckpt);
	block_t nat_bits_addr;

	if (!enabled_nat_bits(sbi, NULL))
		return 0;

	nm_i->nat_bits_blocks = F2FS_BYTES_TO_BLK((nat_bits_bytes << 1) + 8 +
						F2FS_BLKSIZE - 1);
	nm_i->nat_bits = kzalloc(nm_i->nat_bits_blocks << F2FS_BLKSIZE_BITS,
						GFP_KERNEL);
	if (!nm_i->nat_bits)
		return -ENOMEM;

	nat_bits_addr = __start_cp_addr(sbi) + sbi->blocks_per_seg -
						nm_i->nat_bits_blocks;
	for (i = 0; i < nm_i->nat_bits_blocks; i++) {
		struct page *page = get_meta_page(sbi, nat_bits_addr++);

		memcpy(nm_i->nat_bits + (i << F2FS_BLKSIZE_BITS),
					page_address(page), F2FS_BLKSIZE);
		f2fs_put_page(page, 1);
	}

	cp_ver |= (cur_cp_crc(ckpt) << 32);
	if (cpu_to_le64(cp_ver) != *(__le64 *)nm_i->nat_bits) {
		disable_nat_bits(sbi, true);
		return 0;
	}

	nm_i->full_nat_bits = nm_i->nat_bits + 8;
	nm_i->empty_nat_bits = nm_i->full_nat_bits + nat_bits_bytes;

	f2fs_msg(sbi->sb, KERN_NOTICE, "Found nat_bits in checkpoint");
	return 0;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.