static void hns_nic_rx_checksum(struct hns_nic_ring_data *ring_data,
				struct sk_buff *skb, u32 flag)
{
	struct net_device *netdev = ring_data->napi.dev;
	u32 l3id;
	u32 l4id;

	/* check if RX checksum offload is enabled */
	if (unlikely(!(netdev->features & NETIF_F_RXCSUM)))
		return;

	/* In hardware, we only support checksum for the following protocols:
	 * 1) IPv4,
	 * 2) TCP(over IPv4 or IPv6),
	 * 3) UDP(over IPv4 or IPv6),
	 * 4) SCTP(over IPv4 or IPv6)
	 * but we support many L3(IPv4, IPv6, MPLS, PPPoE etc) and L4(TCP,
	 * UDP, GRE, SCTP, IGMP, ICMP etc.) protocols.
	 *
	 * Hardware limitation:
	 * Our present hardware RX Descriptor lacks L3/L4 checksum "Status &
	 * Error" bit (which usually can be used to indicate whether checksum
	 * was calculated by the hardware and if there was any error encountered
	 * during checksum calculation).
	 *
	 * Software workaround:
	 * We do get info within the RX descriptor about the kind of L3/L4
	 * protocol coming in the packet and the error status. These errors
	 * might not just be checksum errors but could be related to version,
	 * length of IPv4, UDP, TCP etc.
	 * Because there is no-way of knowing if it is a L3/L4 error due to bad
	 * checksum or any other L3/L4 error, we will not (cannot) convey
	 * checksum status for such cases to upper stack and will not maintain
	 * the RX L3/L4 checksum counters as well.
	 */

	l3id = hnae_get_field(flag, HNS_RXD_L3ID_M, HNS_RXD_L3ID_S);
	l4id = hnae_get_field(flag, HNS_RXD_L4ID_M, HNS_RXD_L4ID_S);

	/*  check L3 protocol for which checksum is supported */
	if ((l3id != HNS_RX_FLAG_L3ID_IPV4) && (l3id != HNS_RX_FLAG_L3ID_IPV6))
		return;

	/* check for any(not just checksum)flagged L3 protocol errors */
	if (unlikely(hnae_get_bit(flag, HNS_RXD_L3E_B)))
		return;

	/* we do not support checksum of fragmented packets */
	if (unlikely(hnae_get_bit(flag, HNS_RXD_FRAG_B)))
		return;

	/*  check L4 protocol for which checksum is supported */
	if ((l4id != HNS_RX_FLAG_L4ID_TCP) &&
	    (l4id != HNS_RX_FLAG_L4ID_UDP) &&
	    (l4id != HNS_RX_FLAG_L4ID_SCTP))
		return;

	/* check for any(not just checksum)flagged L4 protocol errors */
	if (unlikely(hnae_get_bit(flag, HNS_RXD_L4E_B)))
		return;

	/* now, this has to be a packet with valid RX checksum */
	skb->ip_summed = CHECKSUM_UNNECESSARY;
}

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.