vrouter crash in AgentDBEntry::ClearRefState

vrouter crashed with following backtrace in solution test run.

3.0.2.0-26~kilo

10.84.5.112:/cs-shared/bugs/<bug-id>/

[New LWP 16921]
[New LWP 16918]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/bin/contrail-vrouter-agent'.
Program terminated with signal SIGABRT, Aborted.
#0 0x00007fded5ab5cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#0 0x00007fded5ab5cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007fded5ab90d8 in __GI_abort () at abort.c:89
#2 0x00007fded5af2394 in __libc_message (do_abort=do_abort@entry=1, fmt=fmt@entry=0x7fded5c00b28 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#3 0x00007fded5afe66e in malloc_printerr (ptr=<optimized out>, str=0x7fded5c00cf0 "double free or corruption (fasttop)", action=1) at malloc.c:4996
#4 _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3840
#5 0x0000000000ac0dbc in AgentDBEntry::ClearRefState() const ()
#6 0x0000000000c388f4 in ?? ()
#7 0x0000000000c38cf9 in PktFlowInfo::Process(PktInfo const*, PktControlInfo*, PktControlInfo*) ()
#8 0x0000000000c44acd in FlowHandler::Run() ()
#9 0x0000000000c40fe4 in Proto::ProcessProto(boost::shared_ptr<PktInfo>) ()
#10 0x0000000000c26958 in FlowProto::FlowEventHandler(FlowEvent*, FlowTable*) ()
#11 0x0000000000c2c2df in QueueTaskRunner<FlowEvent*, WorkQueue<FlowEvent*> >::Run() ()
#12 0x0000000001186b3c in TaskImpl::execute() ()
#13 0x00007fded6684b3a in ?? () from /usr/lib/libtbb.so.2
#14 0x00007fded6680816 in ?? () from /usr/lib/libtbb.so.2
#15 0x00007fded667ff4b in ?? () from /usr/lib/libtbb.so.2
#16 0x00007fded667c0ff in ?? () from /usr/lib/libtbb.so.2
#17 0x00007fded667c2f9 in ?? () from /usr/lib/libtbb.so.2
#18 0x00007fded68a0182 in start_thread (arg=0x7fdecf13c700) at pthread_create.c:312
#19 0x00007fded5b7947d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111