r0 = socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$sock_ipv6_tunnel_SIOCDELTUNNEL(r0, 0x89f2, &(0x7f0000003940)={'sit0\x00', &(0x7f00000038c0)={'syztnl1\x00', 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @private0, @private0}})