void __f2fs_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
				block_t old_blkaddr, block_t new_blkaddr,
				bool recover_curseg, bool recover_newaddr)
{
	struct sit_info *sit_i = SIT_I(sbi);
	struct curseg_info *curseg;
	unsigned int segno, old_cursegno;
	struct seg_entry *se;
	int type;
	unsigned short old_blkoff;

	segno = GET_SEGNO(sbi, new_blkaddr);
	se = get_seg_entry(sbi, segno);
	type = se->type;

	if (!recover_curseg) {
		/* for recovery flow */
		if (se->valid_blocks == 0 && !IS_CURSEG(sbi, segno)) {
			if (old_blkaddr == NULL_ADDR)
				type = CURSEG_COLD_DATA;
			else
				type = CURSEG_WARM_DATA;
		}
	} else {
		if (!IS_CURSEG(sbi, segno))
			type = CURSEG_WARM_DATA;
	}

	curseg = CURSEG_I(sbi, type);

	mutex_lock(&curseg->curseg_mutex);
	mutex_lock(&sit_i->sentry_lock);

	old_cursegno = curseg->segno;
	old_blkoff = curseg->next_blkoff;

	/* change the current segment */
	if (segno != curseg->segno) {
		curseg->next_segno = segno;
		change_curseg(sbi, type);
	}

	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
	__add_sum_entry(sbi, type, sum);

	if (!recover_curseg || recover_newaddr)
		update_sit_entry(sbi, new_blkaddr, 1);
	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
		update_sit_entry(sbi, old_blkaddr, -1);

	locate_dirty_segment(sbi, GET_SEGNO(sbi, old_blkaddr));
	locate_dirty_segment(sbi, GET_SEGNO(sbi, new_blkaddr));

	locate_dirty_segment(sbi, old_cursegno);

	if (recover_curseg) {
		if (old_cursegno != curseg->segno) {
			curseg->next_segno = old_cursegno;
			change_curseg(sbi, type);
		}
		curseg->next_blkoff = old_blkoff;
	}

	mutex_unlock(&sit_i->sentry_lock);
	mutex_unlock(&curseg->curseg_mutex);
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.