fix data race

Closes #1442

```
WARNING: DATA RACE
Write at 0x00c4209de7c8 by goroutine 23:
  github.com/tendermint/tendermint/types.(*Block).fillHeader()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:88 +0x157
  github.com/tendermint/tendermint/types.(*Block).Hash()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:104 +0x121
  github.com/tendermint/tendermint/types.(*Block).HashesTo()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:135 +0x4f
  github.com/tendermint/tendermint/consensus.(*ConsensusState).enterPrecommit()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1037 +0x182d
  github.com/tendermint/tendermint/consensus.(*ConsensusState).addVote()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1425 +0x1a6c
  github.com/tendermint/tendermint/consensus.(*ConsensusState).tryAddVote()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1318 +0x77
  github.com/tendermint/tendermint/consensus.(*ConsensusState).handleMsg()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:581 +0x7a9
  github.com/tendermint/tendermint/consensus.(*ConsensusState).receiveRoutine()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:539 +0x6c3

Previous read at 0x00c4209de7c8 by goroutine 47:
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*HexBytes).MarshalJSON()
      <autogenerated>:1 +0x52
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.invokeMarshalJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:433 +0x88
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:82 +0x8d2
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).MarshalJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/amino.go:296 +0x182
  github.com/tendermint/tendermint/rpc/lib/types.NewRPCSuccessResponse()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/types/types.go:100 +0x12c
  github.com/tendermint/tendermint/rpc/lib/server.makeJSONRPCHandler.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/handlers.go:152 +0xab7
  net/http.HandlerFunc.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:1918 +0x51
  net/http.(*ServeMux).ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:2254 +0xa2
  github.com/tendermint/tendermint/rpc/lib/server.RecoverAndLogHandler.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/http_server.go:138 +0x4fa
  net/http.HandlerFunc.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:1918 +0x51
  net/http.serverHandler.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:2619 +0xbc
  net/http.(*conn).serve()
      /usr/lib/go-1.9/src/net/http/server.go:1801 +0x83b

Goroutine 23 (running) created at:
  github.com/tendermint/tendermint/consensus.(*ConsensusState).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:250 +0x35b
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/consensus.(*ConsensusReactor).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/reactor.go:69 +0x1b4
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/consensus.(*ConsensusReactor).Start()
      <autogenerated>:1 +0x43
  github.com/tendermint/tendermint/p2p.(*Switch).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/p2p/switch.go:177 +0x124
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/node.(*Node).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/node/node.go:416 +0xa1b
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/rpc/test.StartTendermint()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/test/helpers.go:100 +0x5b
  github.com/tendermint/tendermint/rpc/client_test.TestMain()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/client/main_test.go:17 +0x4c
  main.main()
      github.com/tendermint/tendermint/rpc/client/_test/_testmain.go:76 +0x1cd

Goroutine 47 (running) created at:
  net/http.(*Server).Serve()
      /usr/lib/go-1.9/src/net/http/server.go:2720 +0x37c
  net/http.Serve()
      /usr/lib/go-1.9/src/net/http/server.go:2323 +0xe2
  github.com/tendermint/tendermint/rpc/lib/server.StartHTTPServer.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/http_server.go:35 +0xb3
```

consensus/reactor.go

@@ -9,7 +9,7 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/tendermint/go-amino"
+	amino "github.com/tendermint/go-amino"
 	cmn "github.com/tendermint/tmlibs/common"
 	"github.com/tendermint/tmlibs/log"
 
@@ -838,8 +838,8 @@ var (
 	ErrPeerStateInvalidStartTime = errors.New("Error peer state invalid startTime")
 )
 
-// PeerState contains the known state of a peer, including its connection
-// and threadsafe access to its PeerRoundState.
+// PeerState contains the known state of a peer, including its connection and
+// threadsafe access to its PeerRoundState.
 type PeerState struct {
 	Peer   p2p.Peer
 	logger log.Logger
@@ -878,12 +878,14 @@ func NewPeerState(peer p2p.Peer) *PeerState {
 	}
 }
 
+// SetLogger allows to set a logger on the peer state. Returns the peer state
+// itself.
 func (ps *PeerState) SetLogger(logger log.Logger) *PeerState {
 	ps.logger = logger
 	return ps
 }
 
-// GetRoundState returns an atomic snapshot of the PeerRoundState.
+// GetRoundState returns an shallow copy of the PeerRoundState.
 // There's no point in mutating it since it won't change PeerState.
 func (ps *PeerState) GetRoundState() *cstypes.PeerRoundState {
 	ps.mtx.Lock()
@@ -893,6 +895,14 @@ func (ps *PeerState) GetRoundState() *cstypes.PeerRoundState {
 	return &prs
 }
 
+// GetRoundStateJSON returns a json of PeerRoundState, marshalled using go-amino.
+func (ps *PeerState) GetRoundStateJSON() ([]byte, error) {
+	ps.mtx.Lock()
+	defer ps.mtx.Unlock()
+
+	return cdc.MarshalJSON(ps.PeerRoundState)
+}
+
 // GetHeight returns an atomic snapshot of the PeerRoundState's height
 // used by the mempool to ensure peers are caught up before broadcasting new txs
 func (ps *PeerState) GetHeight() int64 {
@@ -1055,7 +1065,7 @@ func (ps *PeerState) ensureCatchupCommitRound(height int64, round int, numValida
 	}
 }
 
-// EnsureVoteVitArrays ensures the bit-arrays have been allocated for tracking
+// EnsureVoteBitArrays ensures the bit-arrays have been allocated for tracking
 // what votes this peer has received.
 // NOTE: It's important to make sure that numValidators actually matches
 // what the node sees as the number of validators for height.

consensus/state.go

@@ -168,18 +168,23 @@ func (cs *ConsensusState) GetState() sm.State {
 	return cs.state.Copy()
 }
 
-// GetRoundState returns a copy of the internal consensus state.
+// GetRoundState returns a shallow copy of the internal consensus state.
 func (cs *ConsensusState) GetRoundState() *cstypes.RoundState {
 	cs.mtx.Lock()
 	defer cs.mtx.Unlock()
-	return cs.getRoundState()
-}
 
-func (cs *ConsensusState) getRoundState() *cstypes.RoundState {
 	rs := cs.RoundState // copy
 	return &rs
 }
 
+// GetRoundStateJSON returns a json of RoundState, marshalled using go-amino.
+func (cs *ConsensusState) GetRoundStateJSON() ([]byte, error) {
+	cs.mtx.Lock()
+	defer cs.mtx.Unlock()
+
+	return cdc.MarshalJSON(cs.RoundState)
+}
+
 // GetValidators returns a copy of the current validators.
 func (cs *ConsensusState) GetValidators() (int64, []*types.Validator) {
 	cs.mtx.Lock()

consensus/types/state.go

@@ -52,7 +52,7 @@ func (rs RoundStepType) String() string {
 //-----------------------------------------------------------------------------
 
 // RoundState defines the internal consensus state.
-// It is Immutable when returned from ConsensusState.GetRoundState()
+// It should be immutable when returned from ConsensusState.GetRoundState(), but it's not.
 // TODO: Actually, only the top pointer is copied,
 // so access to field pointers is still racey
 // NOTE: Not thread safe. Should only be manipulated by functions downstream

rpc/core/consensus.go

@@ -1,8 +1,9 @@
 package core
 
 import (
+	"encoding/json"
+
 	cm "github.com/tendermint/tendermint/consensus"
-	cstypes "github.com/tendermint/tendermint/consensus/types"
 	p2p "github.com/tendermint/tendermint/p2p"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 	sm "github.com/tendermint/tendermint/state"
@@ -58,7 +59,7 @@ func Validators(heightPtr *int64) (*ctypes.ResultValidators, error) {
 	return &ctypes.ResultValidators{height, validators.Validators}, nil
 }
 
-// Dump consensus state.
+// DumpConsensusState dumps consensus state.
 //
 // ```shell
 // curl 'localhost:46657/dump_consensus_state'
@@ -83,11 +84,18 @@ func Validators(heightPtr *int64) (*ctypes.ResultValidators, error) {
 // }
 // ```
 func DumpConsensusState() (*ctypes.ResultDumpConsensusState, error) {
-	peerRoundStates := make(map[p2p.ID]*cstypes.PeerRoundState)
+	peerRoundStates := make(map[p2p.ID]json.RawMessage)
 	for _, peer := range p2pSwitch.Peers().List() {
 		peerState := peer.Get(types.PeerStateKey).(*cm.PeerState)
-		peerRoundState := peerState.GetRoundState()
+		peerRoundState, err := peerState.GetRoundStateJSON()
+		if err != nil {
+			return nil, err
+		}
 		peerRoundStates[peer.ID()] = peerRoundState
 	}
-	return &ctypes.ResultDumpConsensusState{consensusState.GetRoundState(), peerRoundStates}, nil
+	roundState, err := consensusState.GetRoundStateJSON()
+	if err != nil {
+		return nil, err
+	}
+	return &ctypes.ResultDumpConsensusState{roundState, peerRoundStates}, nil
 }

rpc/core/pipe.go

@@ -3,9 +3,8 @@ package core
 import (
 	"time"
 
-	"github.com/tendermint/go-crypto"
+	crypto "github.com/tendermint/go-crypto"
 	"github.com/tendermint/tendermint/consensus"
-	cstypes "github.com/tendermint/tendermint/consensus/types"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
@@ -23,7 +22,7 @@ var subscribeTimeout = 5 * time.Second
 type Consensus interface {
 	GetState() sm.State
 	GetValidators() (int64, []*types.Validator)
-	GetRoundState() *cstypes.RoundState
+	GetRoundStateJSON() ([]byte, error)
 }
 
 type P2P interface {

rpc/core/types/responses.go

@@ -1,6 +1,7 @@
 package core_types
 
 import (
+	"encoding/json"
 	"strings"
 	"time"
 
@@ -8,7 +9,6 @@ import (
 	crypto "github.com/tendermint/go-crypto"
 	cmn "github.com/tendermint/tmlibs/common"
 
-	cstypes "github.com/tendermint/tendermint/consensus/types"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
@@ -109,8 +109,8 @@ type ResultValidators struct {
 }
 
 type ResultDumpConsensusState struct {
-	RoundState      *cstypes.RoundState                `json:"round_state"`
-	PeerRoundStates map[p2p.ID]*cstypes.PeerRoundState `json:"peer_round_states"`
+	RoundState      json.RawMessage            `json:"round_state"`
+	PeerRoundStates map[p2p.ID]json.RawMessage `json:"peer_round_states"`
 }
 
 type ResultBroadcastTx struct {