failure of sockepair -yy

gistfile1.txt

socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG) = 4
sendmsg(4, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=40, type=0x14 /* NLMSG_??? */, flags=NLM_F_REQUEST, seq=0, pid=0}, "\x01\x00\x00\x00\xff\xff\xff\xff\x83\x9f\x6b\x00\x05\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff"}, iov_len=40}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 40
recvmsg(4, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=60, type=NLMSG_ERROR, flags=0, seq=0, pid=14881}, {error=-ENOENT, msg={{len=40, type=SOCK_DIAG_BY_FAMILY, flags=NLM_F_REQUEST, seq=0, pid=0}, {sdiag_family=AF_UNIX, sdiag_protocol=0, udiag_states=1<<TCP_ESTABLISHED|1<<TCP_SYN_SENT|1<<TCP_SYN_RECV|1<<TCP_FIN_WAIT1|1<<TCP_FIN_WAIT2|1<<TCP_TIME_WAIT|1<<TCP_CLOSE|1<<TCP_CLOSE_WAIT|1<<TCP_LAST_ACK|1<<TCP_LISTEN|1<<TCP_CLOSING|1<<TCP_NEW_SYN_RECV|0xffffe001, udiag_ino=7053187, udiag_show=UDIAG_SHOW_NAME|UDIAG_SHOW_PEER, udiag_cookie=[4294967295, 4294967295]}}}}, iov_len=8192}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 60
write(3, "UNIX:[7053186]>, 30<", 20)    = 20