static int fanout_set_data(struct packet_sock *po, char __user *data,
			   unsigned int len)
{
	switch (po->fanout->type) {
	case PACKET_FANOUT_CBPF:
		return fanout_set_data_cbpf(po, data, len);
	case PACKET_FANOUT_EBPF:
		return fanout_set_data_ebpf(po, data, len);
	default:
		return -EINVAL;
	};
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.