r0 = socket$inet6_udp(0xa, 0x2, 0x0) connect$inet6(r0, &(0x7f0000000000)={0xa, 0x0, 0x0, @ipv4={'\x00', '\xff\xff', @empty}}, 0x1c) setsockopt$inet6_IPV6_ADDRFORM(r0, 0x29, 0x1, &(0x7f00000000c0), 0x4) r1 = socket$inet6_udp(0xa, 0x2, 0x0) r2 = dup2(r0, r1) r3 = syz_open_procfs(0xffffffffffffffff, &(0x7f0000000080)='mounts\x00') recvmsg$unix(r2, &(0x7f0000002c80)={0x0, 0x0, 0x0}, 0x0) sendfile(r1, r3, 0x0, 0xffd0)