static ssize_t ucma_query_route(struct ucma_file *file,
				const char __user *inbuf,
				int in_len, int out_len)
{
	struct rdma_ucm_query cmd;
	struct rdma_ucm_query_route_resp resp;
	struct ucma_context *ctx;
	struct sockaddr *addr;
	int ret = 0;

	if (out_len < sizeof(resp))
		return -ENOSPC;

	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
		return -EFAULT;

	ctx = ucma_get_ctx(file, cmd.id);
	if (IS_ERR(ctx))
		return PTR_ERR(ctx);

	memset(&resp, 0, sizeof resp);
	addr = (struct sockaddr *) &ctx->cm_id->route.addr.src_addr;
	memcpy(&resp.src_addr, addr, addr->sa_family == AF_INET ?
				     sizeof(struct sockaddr_in) :
				     sizeof(struct sockaddr_in6));
	addr = (struct sockaddr *) &ctx->cm_id->route.addr.dst_addr;
	memcpy(&resp.dst_addr, addr, addr->sa_family == AF_INET ?
				     sizeof(struct sockaddr_in) :
				     sizeof(struct sockaddr_in6));
	if (!ctx->cm_id->device)
		goto out;

	resp.node_guid = (__force __u64) ctx->cm_id->device->node_guid;
	resp.port_num = ctx->cm_id->port_num;

	if (rdma_cap_ib_sa(ctx->cm_id->device, ctx->cm_id->port_num))
		ucma_copy_ib_route(&resp, &ctx->cm_id->route);
	else if (rdma_protocol_roce(ctx->cm_id->device, ctx->cm_id->port_num))
		ucma_copy_iboe_route(&resp, &ctx->cm_id->route);
	else if (rdma_protocol_iwarp(ctx->cm_id->device, ctx->cm_id->port_num))
		ucma_copy_iw_route(&resp, &ctx->cm_id->route);

out:
	if (copy_to_user(u64_to_user_ptr(cmd.response),
			 &resp, sizeof(resp)))
		ret = -EFAULT;

	ucma_put_ctx(ctx);
	return ret;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.