One flow stuck in hold forever on a setup

R3.0.20 Build 33 with latest contrail-vrouter-agent from praveen

The traffic generator was sending 1K pps of udp traffic from MX via a VM

It was seen that 4k flows were created fine.
But one of them is stuck in HOLD state

980152 10.11.1.2:68 17 (5)
                         10.11.2.2:63
(Gen: 72, K(nh):63, Action:H, Flags:, S(nh):0, Stats:185/20350, SPort 0)

In agent flow trace :

2016-05-06 00:29:58.763 FlowTrace: operation = ADD info= [ gen_id = 72 flow_index = 980152 nh_id = 63 source_ip = 10.11.1.2 source_port = 68 destination_ip = 10.11.2.2 destination_port = 63 protocol = 17 vrf = 4294967295 mirror_l= [ [ ] ] mirror_vrf = 65535 implicit_deny = 0 short_flow = 1 source_vn_list= [ [ (*_iter95) = __UNKNOWN__, ] ] dest_vn_list= [ [ (*_iter96) = __UNKNOWN__, ] ] source_vn_match = dest_vn_match = source_sg_id_l= [ [ ] ] dest_sg_id_l= [ [ ] ] vrf_assign = l3_flow = 1 smac = 00:00:00:00:00:00 dmac = 00:00:00:00:00:00 drop_reason = UNKNOWN table_id = 3 ] file = controller/src/vnsw/agent/pkt/flow_mgmt.cc line = 484
2016-05-06 00:29:58.861 FlowTrace: operation = DEL info= [ gen_id = 72 flow_index = 980152 nh_id = 63 source_ip = 10.11.1.2 source_port = 68 destination_ip = 10.11.2.2 destination_port = 63 protocol = 17 vrf = 4294967295 mirror_l= [ [ ] ] mirror_vrf = 65535 implicit_deny = 0 short_flow = 1 source_vn_list= [ [ (*_iter95) = __UNKNOWN__, ] ] dest_vn_list= [ [ (*_iter96) = __UNKNOWN__, ] ] source_vn_match = dest_vn_match = source_sg_id_l= [ [ ] ] dest_sg_id_l= [ [ ] ] vrf_assign = l3_flow = 1 smac = 00:00:00:00:00:00 dmac = 00:00:00:00:00:00 drop_reason = UNKNOWN table_id = 3 ] file = controller/src/vnsw/agent/pkt/flow_mgmt.cc line = 484

---

2016-05-06 00:38:18.187 FlowTrace: operation = ADD info= [ gen_id = 73 flow_index = 980152 nh_id = 63 source_ip = 10.11.1.2 source_port = 68 destination_ip = 10.11.2.2 destination_port = 63 protocol = 17 vrf = 4294967295 mirror_l= [ [ ] ] mirror_vrf = 65535 implicit_deny = 0 short_flow = 1 source_vn_list= [ [ (*_iter95) = __UNKNOWN__, ] ] dest_vn_list= [ [ (*_iter96) = __UNKNOWN__, ] ] source_vn_match = dest_vn_match = source_sg_id_l= [ [ ] ] dest_sg_id_l= [ [ ] ] vrf_assign = l3_flow = 1 smac = 00:00:00:00:00:00 dmac = 00:00:00:00:00:00 drop_reason = UNKNOWN table_id = 3 ] file = controller/src/vnsw/agent/pkt/flow_mgmt.cc line = 484
2016-05-06 00:38:18.224 FlowTrace: operation = DEL info= [ gen_id = 73 flow_index = 980152 nh_id = 63 source_ip = 10.11.1.2 source_port = 68 destination_ip = 10.11.2.2 destination_port = 63 protocol = 17 vrf = 4294967295 mirror_l= [ [ ] ] mirror_vrf = 65535 implicit_deny = 0 short_flow = 1 source_vn_list= [ [ (*_iter95) = __UNKNOWN__, ] ] dest_vn_list= [ [ (*_iter96) = __UNKNOWN__, ] ] source_vn_match = dest_vn_match = source_sg_id_l= [ [ ] ] dest_sg_id_l= [ [ ] ] vrf_assign = l3_flow = 1 smac = 00:00:00:00:00:00 dmac = 00:00:00:00:00:00 drop_reason = UNKNOWN table_id = 3 ] file = controller/src/vnsw/agent/pkt/flow_mgmt.cc line = 484

vrouter --info :

vRouter module version 3.0.2.0 (Built by contrail-builder@contrail-ec-build16 on 2016-04-29 16:28:31.068957)

Startup parameters
    Interfaces limit 4352
    VRF tables limit 4096
    NextHops limit 65536
    MPLS Labels limit 5120
    Bridge Table limit 262144
    Bridge Table Overflow limit 53248
    Flow Table limit 4194304
    Flow Table overflow limit 839680
    Mirror entries limit 255

Runtime parameters
  Performance tweaks
    GRO 1
    Segmentation in software 1
  TCP MSS adjust settings
    TCP MSS on packets from VM 1
    TCP MSS on packet sent to VM 1
  RPS settings
    RPS after pulling inner hdr (perfr1) 0
    RPS after GRO on pkt1 (perfr2) 1
    RPS from phys rx handler (perfr3) 1
    Pull inner header (faster version) 1
    CPU to send pkts to, if perfr1 set 0
    CPU to send pkts to, if perfr2 set 0
    CPU to send pkts to, if perfr3 set 0
  Other settings
    NIC cksum offload for outer UDP hdr 0
    Flow hold limit: 4096
    MPLS over UDP globally 0
    Used Flow entries 3999
    Used Over Flow entries 0
    Used Bridge entries 30
    Used Over Flow bridge entries 0

root@nodek1:/var/log/nova#