perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
			     struct list_head *filters)
{
	struct perf_addr_filter *filter = NULL;
	char *start, *orig, *filename = NULL;
	struct path path;
	substring_t args[MAX_OPT_ARGS];
	int state = IF_STATE_ACTION, token;
	unsigned int kernel = 0;
	int ret = -EINVAL;

	orig = fstr = kstrdup(fstr, GFP_KERNEL);
	if (!fstr)
		return -ENOMEM;

	while ((start = strsep(&fstr, " ,\n")) != NULL) {
		ret = -EINVAL;

		if (!*start)
			continue;

		/* filter definition begins */
		if (state == IF_STATE_ACTION) {
			filter = perf_addr_filter_new(event, filters);
			if (!filter)
				goto fail;
		}

		token = match_token(start, if_tokens, args);
		switch (token) {
		case IF_ACT_FILTER:
		case IF_ACT_START:
			filter->filter = 1;

		case IF_ACT_STOP:
			if (state != IF_STATE_ACTION)
				goto fail;

			state = IF_STATE_SOURCE;
			break;

		case IF_SRC_KERNELADDR:
		case IF_SRC_KERNEL:
			kernel = 1;

		case IF_SRC_FILEADDR:
		case IF_SRC_FILE:
			if (state != IF_STATE_SOURCE)
				goto fail;

			if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
				filter->range = 1;

			*args[0].to = 0;
			ret = kstrtoul(args[0].from, 0, &filter->offset);
			if (ret)
				goto fail;

			if (filter->range) {
				*args[1].to = 0;
				ret = kstrtoul(args[1].from, 0, &filter->size);
				if (ret)
					goto fail;
			}

			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
				int fpos = filter->range ? 2 : 1;

				filename = match_strdup(&args[fpos]);
				if (!filename) {
					ret = -ENOMEM;
					goto fail;
				}
			}

			state = IF_STATE_END;
			break;

		default:
			goto fail;
		}

		/*
		 * Filter definition is fully parsed, validate and install it.
		 * Make sure that it doesn't contradict itself or the event's
		 * attribute.
		 */
		if (state == IF_STATE_END) {
			ret = -EINVAL;
			if (kernel && event->attr.exclude_kernel)
				goto fail;

			if (!kernel) {
				if (!filename)
					goto fail;

				/*
				 * For now, we only support file-based filters
				 * in per-task events; doing so for CPU-wide
				 * events requires additional context switching
				 * trickery, since same object code will be
				 * mapped at different virtual addresses in
				 * different processes.
				 */
				ret = -EOPNOTSUPP;
				if (!event->ctx->task)
					goto fail_free_name;

				/* look up the path and grab its inode */
				ret = kern_path(filename, LOOKUP_FOLLOW, &path);
				if (ret)
					goto fail_free_name;

				filter->inode = igrab(d_inode(path.dentry));
				path_put(&path);
				kfree(filename);
				filename = NULL;

				ret = -EINVAL;
				if (!filter->inode ||
				    !S_ISREG(filter->inode->i_mode))
					/* free_filters_list() will iput() */
					goto fail;

				event->addr_filters.nr_file_filters++;
			}

			/* ready to consume more filters */
			state = IF_STATE_ACTION;
			filter = NULL;
		}
	}

	if (state != IF_STATE_ACTION)
		goto fail;

	kfree(orig);

	return 0;

fail_free_name:
	kfree(filename);
fail:
	free_filters_list(filters);
	kfree(orig);

	return ret;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.