core: Lock entire lattice.ProcessBlock (#259)

* Lock entire ProcessBlock

* Lock Consensus.processBlock

2 files changed, 7 insertions, 2 deletions

diff --git a/core/consensus.go b/core/consensus.go
index ab59a67..05f93e1 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -830,6 +830,10 @@ func (con *Consensus) processBlock(block *types.Block) (err error) {
 	if err = con.db.Put(*block); err != nil && err != blockdb.ErrBlockExists {
 		return
 	}
+	con.lock.Lock()
+	defer con.lock.Unlock()
+	// Block processed by lattice can be out-of-order. But the output of lattice
+	// (deliveredBlocks) cannot.
 	deliveredBlocks, err := con.lattice.ProcessBlock(block)
 	if err != nil {
 		return
diff --git a/core/lattice.go b/core/lattice.go
index 69ad51c..06005c1 100644
--- a/core/lattice.go
+++ b/core/lattice.go
@@ -161,8 +161,6 @@ func (s *Lattice) SanityCheck(b *types.Block) (err error) {
 // NOTE: assume the block passed sanity check.
 func (s *Lattice) addBlockToLattice(
 	input *types.Block) (outputBlocks []*types.Block, err error) {
-	s.lock.Lock()
-	defer s.lock.Unlock()
 	if tip := s.data.chains[input.Position.ChainID].tip; tip != nil {
 		if !input.Position.Newer(&tip.Position) {
 			return
@@ -226,6 +224,9 @@ func (s *Lattice) ProcessBlock(
 		deliveredMode uint32
 	)
 
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
 	if inLattice, err = s.addBlockToLattice(input); err != nil {
 		return
 	}