3 files changed, 21 insertions, 1 deletions
diff --git a/core/agreement-mgr.go b/core/agreement-mgr.go
index 4e6f230..af0adf2 100644
--- a/core/agreement-mgr.go
+++ b/core/agreement-mgr.go
@@ -257,6 +257,7 @@ func (mgr *agreementMgr) processVote(v *types.Vote) (err error) {
 	}
 	if err = mgr.baModule.processVote(v); err == nil {
 		mgr.baModule.updateFilter(mgr.voteFilter)
+		mgr.voteFilter.AddVote(v)
 	}
 	return
 }
diff --git a/core/utils/vote-filter.go b/core/utils/vote-filter.go
index a199027..2fc18bb 100644
--- a/core/utils/vote-filter.go
+++ b/core/utils/vote-filter.go
@@ -24,6 +24,7 @@ import (
 // VoteFilter filters votes that are useless for now.
 // To maximize performance, this structure is not thread-safe and will never be.
 type VoteFilter struct {
+	Voted    map[types.VoteHeader]struct{}
 	Height   uint64
 	LockIter uint64
 	Period   uint64
@@ -32,7 +33,9 @@ type VoteFilter struct {
 
 // NewVoteFilter creates a new vote filter instance.
 func NewVoteFilter() *VoteFilter {
-	return &VoteFilter{}
+	return &VoteFilter{
+		Voted: make(map[types.VoteHeader]struct{}),
+	}
 }
 
 // Filter checks if the vote should be filtered out.
@@ -57,5 +60,13 @@ func (vf *VoteFilter) Filter(vote *types.Vote) bool {
 		vote.BlockHash == types.SkipBlockHash {
 		return true
 	}
+	if _, exist := vf.Voted[vote.VoteHeader]; exist {
+		return true
+	}
 	return false
 }
+
+// AddVote to the filter so the same vote will be filtered.
+func (vf *VoteFilter) AddVote(vote *types.Vote) {
+	vf.Voted[vote.VoteHeader] = struct{}{}
+}
diff --git a/core/utils/vote-filter_test.go b/core/utils/vote-filter_test.go
index 88050e1..443efff 100644
--- a/core/utils/vote-filter_test.go
+++ b/core/utils/vote-filter_test.go
@@ -87,6 +87,14 @@ func (s *VoteFilterTestSuite) TestFilterLowerHeight() {
 	s.True(filter.Filter(vote))
 }
 
+func (s *VoteFilterTestSuite) TestFilterSameVote() {
+	filter := NewVoteFilter()
+	vote := types.NewVote(types.VoteCom, common.NewRandomHash(), uint64(5))
+	s.False(filter.Filter(vote))
+	filter.AddVote(vote)
+	s.True(filter.Filter(vote))
+}
+
 func TestVoteFilter(t *testing.T) {
 	suite.Run(t, new(VoteFilterTestSuite))
 }