route leaking between virutal router and master routing table

#on MX :   set chassis fpc 1 pic 0 tunnel-services bandwidth 1g

set interfaces lt-1/0/10 unit 20 encapsulation ethernet
set interfaces lt-1/0/10 unit 20 peer-unit 21
set interfaces lt-1/0/10 unit 20 family inet address 10.17.12.1/30
set interfaces lt-1/0/10 unit 21 encapsulation ethernet
set interfaces lt-1/0/10 unit 21 peer-unit 20
set interfaces lt-1/0/10 unit 21 family inet address 10.17.12.2/30

#to reach the loopback in the VR, static route:
#----------------------------------------------
set routing-options static route 10.17.112.1/32 next-hop 10.17.12.2


lt-1/0/10.20 stay in the base router!
-------------------------------------

lt-1/0/10.21 is attached to the VR:
----------------------------------

#on the VR:
#----------
set routing-instances vr_sender instance-type virtual-router
set routing-instances vr_sender interface lt-1/0/10.21
set routing-instances vr_sender interface lo0.112
set routing-instances vr_sender routing-options static route 0.0.0.0/0 next-table inet.0



test:
-----
root@mx480-re0# run ping routing-instance vr_sender 10.17.12.2
PING 10.17.12.2 (10.17.12.2): 56 data bytes
64 bytes from 10.17.12.2: icmp_seq=0 ttl=64 time=0.044 ms
64 bytes from 10.17.12.2: icmp_seq=1 ttl=64 time=0.049 ms
^C
--- 10.17.12.2 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.044/0.046/0.049/0.003 ms


{master}[edit routing-instances vr_sender interface lt-1/0/10.21]
root@mx480-re0# run ping routing-instance vr_sender 10.17.12.1
PING 10.17.12.1 (10.17.12.1): 56 data bytes
64 bytes from 10.17.12.1: icmp_seq=0 ttl=64 time=1.815 ms
64 bytes from 10.17.12.1: icmp_seq=1 ttl=64 time=0.969 ms