static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
{
	if (commit->parents && commit->parents->next) {
		unsigned n;
		struct treesame_state *st;
		struct commit_list *p;
		unsigned relevant_parents;
		unsigned relevant_change, irrelevant_change;

		st = lookup_decoration(&revs->treesame, &commit->object);
		if (!st)
			die("update_treesame %s", sha1_to_hex(commit->object.sha1));
		relevant_parents = 0;
		relevant_change = irrelevant_change = 0;
		for (p = commit->parents, n = 0; p; n++, p = p->next) {
			if (relevant_commit(p->item)) {
				relevant_change |= !st->treesame[n];
				relevant_parents++;
			} else
				irrelevant_change |= !st->treesame[n];
		}
		if (relevant_parents ? relevant_change : irrelevant_change)
			commit->object.flags &= ~TREESAME;
		else
			commit->object.flags |= TREESAME;
	}

	return commit->object.flags & TREESAME;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.