vrouter agent crashed due to Agent did not receive any delete event from controller, however it received delete even from vrouter as below
This causes to have stale route entries in the vrouter agent causing the crash.
Back trace analysis
>>>>>>>>
#10 0x0000000000fc4931 in PktFlowInfo::Add (this=this@entry=0x7fbd7c96a800, pkt=0x1e87a540, in=in@entry=0x7fbd7c96a780, out=out@entry=0x7fbd7c96a7c0) at controller/src/vnsw/agent/pkt/pkt_flow_info.cc:2160
update = false
sip = {type = <optimized out>, ipv4_address = {addr = {s_addr = 703638678}}, ipv6_address = {addr_ = {in6_u = {u6_addr8 = {<optimized out> <repeats 16 times>}, u6_addr16 = {<optimized out>,
<optimized out>, <optimized out>, <optimized out>, <optimized out>, <optimized out>, <optimized out>, <optimized out>}, u6_addr32 = {<optimized out>, <optimized out>, <optimized out>,
<optimized out>}}}, scope_id = <optimized out>}}
dip = {type = <optimized out>, ipv4_address = {addr = {s_addr = 753970326}}, ipv6_address = {addr = {in6_u = {u6_addr8 = {<optimized out> <repeats 16 times>}, u6_addr16 = {<optimized out>,
<optimized out>}}}, scope_id = 0}}
key = {family = Address::INET, nh = 676, src_addr = {type = boost::asio::ip::address::ipv4, ipv4_address = {addr = {s_addr = 703638678}}, ipv6_address = {addr = {in6_u = {
u6_addr8 = '\000' <repeats 15 times>, u6_addr16 = {0, 0, 0, 0, 0, 0, 0, 0}, u6_addr32 = {0, 0, 0, 0}}}, scope_id = 0}}, dst_addr = {type = boost::asio::ip::address::ipv4,
ipv4_address = {addr = {s_addr = 753970326}}, ipv6_address = {addr = {in6_u = {u6_addr8 = '\000' <repeats 15 times>, u6_addr16 = {0, 0, 0, 0, 0, 0, 0, 0}, u6_addr32 = {0, 0, 0, 0}}},
scope_id = 0}}, protocol = 6 '\006', src_port = 65437, dst_port = 1433}
flow = {px = 0x4facd00}
rflow = {px = 0x5772d00}
PRETTY_FUNCTION = "void PktFlowInfo::Add(const PktInfo*, PktControlInfo*, PktControlInfo*)"
r_sport = <optimized out>
r_dport = <optimized out>
swap_flows = false
tmp = <optimized out>
>>>>>>>>>
This is a known bug
And is fixed in 21.4.L4