static int packet_getsockopt(struct socket *sock, int level, int optname,
			     char __user *optval, int __user *optlen)
{
	int len;
	int val, lv = sizeof(val);
	struct sock *sk = sock->sk;
	struct packet_sock *po = pkt_sk(sk);
	void *data = &val;
	union tpacket_stats_u st;
	struct tpacket_rollover_stats rstats;

	if (level != SOL_PACKET)
		return -ENOPROTOOPT;

	if (get_user(len, optlen))
		return -EFAULT;

	if (len < 0)
		return -EINVAL;

	switch (optname) {
	case PACKET_STATISTICS:
		spin_lock_bh(&sk->sk_receive_queue.lock);
		memcpy(&st, &po->stats, sizeof(st));
		memset(&po->stats, 0, sizeof(po->stats));
		spin_unlock_bh(&sk->sk_receive_queue.lock);

		if (po->tp_version == TPACKET_V3) {
			lv = sizeof(struct tpacket_stats_v3);
			st.stats3.tp_packets += st.stats3.tp_drops;
			data = &st.stats3;
		} else {
			lv = sizeof(struct tpacket_stats);
			st.stats1.tp_packets += st.stats1.tp_drops;
			data = &st.stats1;
		}

		break;
	case PACKET_AUXDATA:
		val = po->auxdata;
		break;
	case PACKET_ORIGDEV:
		val = po->origdev;
		break;
	case PACKET_VNET_HDR:
		val = po->has_vnet_hdr;
		break;
	case PACKET_VERSION:
		val = po->tp_version;
		break;
	case PACKET_HDRLEN:
		if (len > sizeof(int))
			len = sizeof(int);
		if (copy_from_user(&val, optval, len))
			return -EFAULT;
		switch (val) {
		case TPACKET_V1:
			val = sizeof(struct tpacket_hdr);
			break;
		case TPACKET_V2:
			val = sizeof(struct tpacket2_hdr);
			break;
		case TPACKET_V3:
			val = sizeof(struct tpacket3_hdr);
			break;
		default:
			return -EINVAL;
		}
		break;
	case PACKET_RESERVE:
		val = po->tp_reserve;
		break;
	case PACKET_LOSS:
		val = po->tp_loss;
		break;
	case PACKET_TIMESTAMP:
		val = po->tp_tstamp;
		break;
	case PACKET_FANOUT:
		val = (po->fanout ?
		       ((u32)po->fanout->id |
			((u32)po->fanout->type << 16) |
			((u32)po->fanout->flags << 24)) :
		       0);
		break;
	case PACKET_ROLLOVER_STATS:
		if (!po->rollover)
			return -EINVAL;
		rstats.tp_all = atomic_long_read(&po->rollover->num);
		rstats.tp_huge = atomic_long_read(&po->rollover->num_huge);
		rstats.tp_failed = atomic_long_read(&po->rollover->num_failed);
		data = &rstats;
		lv = sizeof(rstats);
		break;
	case PACKET_TX_HAS_OFF:
		val = po->tp_tx_has_off;
		break;
	case PACKET_QDISC_BYPASS:
		val = packet_use_direct_xmit(po);
		break;
	default:
		return -ENOPROTOOPT;
	}

	if (len > lv)
		len = lv;
	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, data, len))
		return -EFAULT;
	return 0;
}

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.