static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
{
	__u32 data;
	int ret;

	data = item_udata(item);

	switch (item->tag) {
	case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
		ret = open_collection(parser, data & 0xff);
		break;
	case HID_MAIN_ITEM_TAG_END_COLLECTION:
		ret = close_collection(parser);
		break;
	case HID_MAIN_ITEM_TAG_INPUT:
		ret = hid_add_field(parser, HID_INPUT_REPORT, data);
		break;
	case HID_MAIN_ITEM_TAG_OUTPUT:
		ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
		break;
	case HID_MAIN_ITEM_TAG_FEATURE:
		ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
		break;
	default:
		hid_err(parser->device, "unknown main item tag 0x%x\n", item->tag);
		ret = 0;
	}

	memset(&parser->local, 0, sizeof(parser->local));	/* Reset the local parser environment */

	return ret;
}

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