static int hid_find_field_early(struct hid_device *hid, unsigned int page,
    unsigned int hid_code, struct hid_field **pfield)
{
	struct hid_report *report;
	struct hid_field *field;
	struct hid_usage *usage;
	int i, j;

	list_for_each_entry(report, &hid->report_enum[HID_OUTPUT_REPORT].report_list, list) {
		for (i = 0; i < report->maxfield; i++) {
			field = report->field[i];
			for (j = 0; j < field->maxusage; j++) {
				usage = &field->usage[j];
				if ((usage->hid & HID_USAGE_PAGE) == page &&
				    (usage->hid & 0xFFFF) == hid_code) {
					*pfield = field;
					return j;
				}
			}
		}
	}
	return -1;
}

The product reads data past the end, or before the beginning, of the intended buffer.