From d0e03f01fc160e13475ea8c677d6e156c12adf54 Mon Sep 17 00:00:00 2001
From: Sam Kleinman <garen@tychoish.com>
Date: Mon, 13 Dec 2021 13:35:32 -0500
Subject: [PATCH] sync: remove special mutexes (#7438)

---
 abci/client/client.go                      |  3 +--
 abci/client/creators.go                    |  4 ++--
 abci/client/grpc_client.go                 |  3 +--
 abci/client/local_client.go                |  8 ++++----
 abci/client/socket_client.go               |  4 ++--
 abci/server/socket_server.go               |  6 +++---
 internal/blocksync/pool.go                 |  6 +++---
 internal/consensus/byzantine_test.go       |  3 +--
 internal/consensus/common_test.go          |  3 +--
 internal/consensus/peer_state.go           |  2 +-
 internal/consensus/reactor.go              |  4 ++--
 internal/consensus/reactor_test.go         |  3 +--
 internal/consensus/state.go                |  4 ++--
 internal/evidence/reactor.go               |  2 +-
 internal/libs/clist/clist.go               |  6 ++----
 internal/libs/flowrate/flowrate.go         |  5 ++---
 internal/libs/sync/deadlock.go             | 18 ------------------
 internal/libs/sync/sync.go                 | 16 ----------------
 internal/libs/tempfile/tempfile.go         |  5 ++---
 internal/libs/timer/throttle_timer.go      |  5 ++---
 internal/libs/timer/throttle_timer_test.go |  5 ++---
 internal/mempool/cache.go                  |  4 ++--
 internal/mempool/ids.go                    |  4 ++--
 internal/mempool/mempool.go                |  4 ++--
 internal/mempool/priority_queue.go         |  5 ++---
 internal/mempool/reactor.go                |  2 +-
 internal/mempool/tx.go                     |  6 +++---
 internal/p2p/conn/connection.go            |  4 ++--
 internal/p2p/conn/secret_connection.go     |  6 +++---
 internal/statesync/chunks.go               |  4 ++--
 internal/statesync/reactor.go              |  4 ++--
 internal/statesync/snapshots.go            |  4 ++--
 internal/statesync/stateprovider.go        |  6 +++---
 internal/statesync/syncer.go               |  4 ++--
 internal/statesync/syncer_test.go          |  3 +--
 libs/events/events.go                      |  8 ++++----
 libs/json/structs.go                       |  5 ++---
 libs/json/types.go                         |  5 ++---
 light/client.go                            |  3 +--
 light/store/db/db.go                       |  4 ++--
 privval/secret_connection.go               |  6 +++---
 privval/signer_endpoint.go                 |  4 ++--
 privval/signer_listener_endpoint.go        |  4 ++--
 privval/signer_server.go                   |  4 ++--
 rpc/client/http/ws.go                      |  4 ++--
 rpc/jsonrpc/client/http_json_client.go     |  6 +++---
 rpc/jsonrpc/client/ws_client.go            |  3 +--
 rpc/jsonrpc/client/ws_client_test.go       |  4 ++--
 types/block.go                             |  4 ++--
 types/part_set.go                          |  4 ++--
 types/vote_set.go                          |  4 ++--
 51 files changed, 98 insertions(+), 149 deletions(-)
 delete mode 100644 internal/libs/sync/deadlock.go
 delete mode 100644 internal/libs/sync/sync.go

diff --git a/abci/client/client.go b/abci/client/client.go
index 1f0017557..d588922f6 100644
--- a/abci/client/client.go
+++ b/abci/client/client.go
@@ -6,7 +6,6 @@ import (
 	"sync"
 
 	"github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 )
@@ -88,7 +87,7 @@ type ReqRes struct {
 	*sync.WaitGroup
 	*types.Response // Not set atomically, so be sure to use WaitGroup.
 
-	mtx  tmsync.Mutex
+	mtx  sync.Mutex
 	done bool                  // Gets set to true once *after* WaitGroup.Done().
 	cb   func(*types.Response) // A single callback that may be set.
 }
diff --git a/abci/client/creators.go b/abci/client/creators.go
index 7cabb2e43..c7220e928 100644
--- a/abci/client/creators.go
+++ b/abci/client/creators.go
@@ -2,9 +2,9 @@ package abciclient
 
 import (
 	"fmt"
+	"sync"
 
 	"github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 )
 
@@ -14,7 +14,7 @@ type Creator func(log.Logger) (Client, error)
 // NewLocalCreator returns a Creator for the given app,
 // which will be running locally.
 func NewLocalCreator(app types.Application) Creator {
-	mtx := new(tmsync.Mutex)
+	mtx := new(sync.Mutex)
 
 	return func(_ log.Logger) (Client, error) {
 		return NewLocalClient(mtx, app), nil
diff --git a/abci/client/grpc_client.go b/abci/client/grpc_client.go
index 3f5da63f7..ee35646f9 100644
--- a/abci/client/grpc_client.go
+++ b/abci/client/grpc_client.go
@@ -10,7 +10,6 @@ import (
 	"google.golang.org/grpc"
 
 	"github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
@@ -27,7 +26,7 @@ type grpcClient struct {
 	conn     *grpc.ClientConn
 	chReqRes chan *ReqRes // dispatches "async" responses to callbacks *in order*, needed by mempool
 
-	mtx   tmsync.Mutex
+	mtx   sync.Mutex
 	addr  string
 	err   error
 	resCb func(*types.Request, *types.Response) // listens to all callbacks
diff --git a/abci/client/local_client.go b/abci/client/local_client.go
index f534a1716..8f2fab4e7 100644
--- a/abci/client/local_client.go
+++ b/abci/client/local_client.go
@@ -2,9 +2,9 @@ package abciclient
 
 import (
 	"context"
+	"sync"
 
 	types "github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -15,7 +15,7 @@ import (
 type localClient struct {
 	service.BaseService
 
-	mtx *tmsync.Mutex
+	mtx *sync.Mutex
 	types.Application
 	Callback
 }
@@ -26,9 +26,9 @@ var _ Client = (*localClient)(nil)
 // methods of the given app.
 //
 // Both Async and Sync methods ignore the given context.Context parameter.
-func NewLocalClient(mtx *tmsync.Mutex, app types.Application) Client {
+func NewLocalClient(mtx *sync.Mutex, app types.Application) Client {
 	if mtx == nil {
-		mtx = new(tmsync.Mutex)
+		mtx = new(sync.Mutex)
 	}
 	cli := &localClient{
 		mtx:         mtx,
diff --git a/abci/client/socket_client.go b/abci/client/socket_client.go
index 562124e6c..84a851f4d 100644
--- a/abci/client/socket_client.go
+++ b/abci/client/socket_client.go
@@ -9,10 +9,10 @@ import (
 	"io"
 	"net"
 	"reflect"
+	"sync"
 	"time"
 
 	"github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
@@ -41,7 +41,7 @@ type socketClient struct {
 
 	reqQueue chan *reqResWithContext
 
-	mtx     tmsync.Mutex
+	mtx     sync.Mutex
 	err     error
 	reqSent *list.List                            // list of requests sent, waiting for response
 	resCb   func(*types.Request, *types.Response) // called on all requests, if set.
diff --git a/abci/server/socket_server.go b/abci/server/socket_server.go
index dd71a5df8..eb959b5b4 100644
--- a/abci/server/socket_server.go
+++ b/abci/server/socket_server.go
@@ -7,9 +7,9 @@ import (
 	"io"
 	"net"
 	"runtime"
+	"sync"
 
 	"github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
@@ -25,11 +25,11 @@ type SocketServer struct {
 	addr     string
 	listener net.Listener
 
-	connsMtx   tmsync.Mutex
+	connsMtx   sync.Mutex
 	conns      map[int]net.Conn
 	nextConnID int
 
-	appMtx tmsync.Mutex
+	appMtx sync.Mutex
 	app    types.Application
 }
 
diff --git a/internal/blocksync/pool.go b/internal/blocksync/pool.go
index 4db0fd900..a06c841fc 100644
--- a/internal/blocksync/pool.go
+++ b/internal/blocksync/pool.go
@@ -5,11 +5,11 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"sync"
 	"sync/atomic"
 	"time"
 
 	"github.com/tendermint/tendermint/internal/libs/flowrate"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/types"
@@ -73,7 +73,7 @@ type BlockPool struct {
 
 	lastAdvance time.Time
 
-	mtx tmsync.RWMutex
+	mtx sync.RWMutex
 	// block requests
 	requesters map[int64]*bpRequester
 	height     int64 // the lowest key in requesters.
@@ -560,7 +560,7 @@ type bpRequester struct {
 	gotBlockCh chan struct{}
 	redoCh     chan types.NodeID // redo may send multitime, add peerId to identify repeat
 
-	mtx    tmsync.Mutex
+	mtx    sync.Mutex
 	peerID types.NodeID
 	block  *types.Block
 }
diff --git a/internal/consensus/byzantine_test.go b/internal/consensus/byzantine_test.go
index 3133e3659..a14af999b 100644
--- a/internal/consensus/byzantine_test.go
+++ b/internal/consensus/byzantine_test.go
@@ -16,7 +16,6 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/internal/eventbus"
 	"github.com/tendermint/tendermint/internal/evidence"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/mempool"
 	"github.com/tendermint/tendermint/internal/p2p"
 	sm "github.com/tendermint/tendermint/internal/state"
@@ -68,7 +67,7 @@ func TestByzantinePrevoteEquivocation(t *testing.T) {
 			blockStore := store.NewBlockStore(blockDB)
 
 			// one for mempool, one for consensus
-			mtx := new(tmsync.Mutex)
+			mtx := new(sync.Mutex)
 			proxyAppConnMem := abciclient.NewLocalClient(mtx, app)
 			proxyAppConnCon := abciclient.NewLocalClient(mtx, app)
 
diff --git a/internal/consensus/common_test.go b/internal/consensus/common_test.go
index 27f9628d1..b8548cdc8 100644
--- a/internal/consensus/common_test.go
+++ b/internal/consensus/common_test.go
@@ -21,7 +21,6 @@ import (
 	"github.com/tendermint/tendermint/config"
 	cstypes "github.com/tendermint/tendermint/internal/consensus/types"
 	"github.com/tendermint/tendermint/internal/eventbus"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/mempool"
 	sm "github.com/tendermint/tendermint/internal/state"
 	"github.com/tendermint/tendermint/internal/store"
@@ -440,7 +439,7 @@ func newStateWithConfigAndBlockStore(
 	blockStore *store.BlockStore,
 ) *State {
 	// one for mempool, one for consensus
-	mtx := new(tmsync.Mutex)
+	mtx := new(sync.Mutex)
 	proxyAppConnMem := abciclient.NewLocalClient(mtx, app)
 	proxyAppConnCon := abciclient.NewLocalClient(mtx, app)
 
diff --git a/internal/consensus/peer_state.go b/internal/consensus/peer_state.go
index 6a64e8e10..ada4b270e 100644
--- a/internal/consensus/peer_state.go
+++ b/internal/consensus/peer_state.go
@@ -40,7 +40,7 @@ type PeerState struct {
 	logger log.Logger
 
 	// NOTE: Modify below using setters, never directly.
-	mtx     tmsync.RWMutex
+	mtx     sync.RWMutex
 	running bool
 	PRS     cstypes.PeerRoundState `json:"round_state"`
 	Stats   *peerStateStats        `json:"stats"`
diff --git a/internal/consensus/reactor.go b/internal/consensus/reactor.go
index ad6a108be..e7ec24159 100644
--- a/internal/consensus/reactor.go
+++ b/internal/consensus/reactor.go
@@ -5,11 +5,11 @@ import (
 	"errors"
 	"fmt"
 	"runtime/debug"
+	"sync"
 	"time"
 
 	cstypes "github.com/tendermint/tendermint/internal/consensus/types"
 	"github.com/tendermint/tendermint/internal/eventbus"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/p2p"
 	sm "github.com/tendermint/tendermint/internal/state"
 	"github.com/tendermint/tendermint/libs/bits"
@@ -117,7 +117,7 @@ type Reactor struct {
 	eventBus *eventbus.EventBus
 	Metrics  *Metrics
 
-	mtx      tmsync.RWMutex
+	mtx      sync.RWMutex
 	peers    map[types.NodeID]*PeerState
 	waitSync bool
 
diff --git a/internal/consensus/reactor_test.go b/internal/consensus/reactor_test.go
index 1788c0d20..ff218cb5f 100644
--- a/internal/consensus/reactor_test.go
+++ b/internal/consensus/reactor_test.go
@@ -21,7 +21,6 @@ import (
 	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/crypto/encoding"
 	"github.com/tendermint/tendermint/internal/eventbus"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/mempool"
 	"github.com/tendermint/tendermint/internal/p2p"
 	"github.com/tendermint/tendermint/internal/p2p/p2ptest"
@@ -392,7 +391,7 @@ func TestReactorWithEvidence(t *testing.T) {
 		blockStore := store.NewBlockStore(blockDB)
 
 		// one for mempool, one for consensus
-		mtx := new(tmsync.Mutex)
+		mtx := new(sync.Mutex)
 		proxyAppConnMem := abciclient.NewLocalClient(mtx, app)
 		proxyAppConnCon := abciclient.NewLocalClient(mtx, app)
 
diff --git a/internal/consensus/state.go b/internal/consensus/state.go
index 051b7afba..f45088352 100644
--- a/internal/consensus/state.go
+++ b/internal/consensus/state.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"os"
 	"runtime/debug"
+	"sync"
 	"time"
 
 	"github.com/gogo/protobuf/proto"
@@ -17,7 +18,6 @@ import (
 	cstypes "github.com/tendermint/tendermint/internal/consensus/types"
 	"github.com/tendermint/tendermint/internal/eventbus"
 	"github.com/tendermint/tendermint/internal/libs/fail"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	sm "github.com/tendermint/tendermint/internal/state"
 	tmevents "github.com/tendermint/tendermint/libs/events"
 	tmjson "github.com/tendermint/tendermint/libs/json"
@@ -100,7 +100,7 @@ type State struct {
 	evpool evidencePool
 
 	// internal state
-	mtx tmsync.RWMutex
+	mtx sync.RWMutex
 	cstypes.RoundState
 	state sm.State // State until height-1.
 	// privValidator pubkey, memoized for the duration of one block
diff --git a/internal/evidence/reactor.go b/internal/evidence/reactor.go
index 62272a810..385308884 100644
--- a/internal/evidence/reactor.go
+++ b/internal/evidence/reactor.go
@@ -53,7 +53,7 @@ type Reactor struct {
 
 	peerWG sync.WaitGroup
 
-	mtx          tmsync.Mutex
+	mtx          sync.Mutex
 	peerRoutines map[types.NodeID]*tmsync.Closer
 }
 
diff --git a/internal/libs/clist/clist.go b/internal/libs/clist/clist.go
index 6cf515706..145c4e4f1 100644
--- a/internal/libs/clist/clist.go
+++ b/internal/libs/clist/clist.go
@@ -14,8 +14,6 @@ to ensure garbage collection of removed elements.
 import (
 	"fmt"
 	"sync"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 // MaxLength is the max allowed number of elements a linked list is
@@ -44,7 +42,7 @@ waiting on NextWait() (since it's just a read operation).
 
 */
 type CElement struct {
-	mtx        tmsync.RWMutex
+	mtx        sync.RWMutex
 	prev       *CElement
 	prevWg     *sync.WaitGroup
 	prevWaitCh chan struct{}
@@ -220,7 +218,7 @@ func (e *CElement) SetRemoved() {
 // Operations are goroutine-safe.
 // Panics if length grows beyond the max.
 type CList struct {
-	mtx    tmsync.RWMutex
+	mtx    sync.RWMutex
 	wg     *sync.WaitGroup
 	waitCh chan struct{}
 	head   *CElement // first element
diff --git a/internal/libs/flowrate/flowrate.go b/internal/libs/flowrate/flowrate.go
index 522c46cc7..2a053805c 100644
--- a/internal/libs/flowrate/flowrate.go
+++ b/internal/libs/flowrate/flowrate.go
@@ -8,14 +8,13 @@ package flowrate
 
 import (
 	"math"
+	"sync"
 	"time"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 // Monitor monitors and limits the transfer rate of a data stream.
 type Monitor struct {
-	mu      tmsync.Mutex  // Mutex guarding access to all internal fields
+	mu      sync.Mutex    // Mutex guarding access to all internal fields
 	active  bool          // Flag indicating an active transfer
 	start   time.Duration // Transfer start time (clock() value)
 	bytes   int64         // Total number of bytes transferred
diff --git a/internal/libs/sync/deadlock.go b/internal/libs/sync/deadlock.go
deleted file mode 100644
index 21b5130ba..000000000
--- a/internal/libs/sync/deadlock.go
+++ /dev/null
@@ -1,18 +0,0 @@
-//go:build deadlock
-// +build deadlock
-
-package sync
-
-import (
-	deadlock "github.com/sasha-s/go-deadlock"
-)
-
-// A Mutex is a mutual exclusion lock.
-type Mutex struct {
-	deadlock.Mutex
-}
-
-// An RWMutex is a reader/writer mutual exclusion lock.
-type RWMutex struct {
-	deadlock.RWMutex
-}
diff --git a/internal/libs/sync/sync.go b/internal/libs/sync/sync.go
deleted file mode 100644
index c6e7101c6..000000000
--- a/internal/libs/sync/sync.go
+++ /dev/null
@@ -1,16 +0,0 @@
-//go:build !deadlock
-// +build !deadlock
-
-package sync
-
-import "sync"
-
-// A Mutex is a mutual exclusion lock.
-type Mutex struct {
-	sync.Mutex
-}
-
-// An RWMutex is a reader/writer mutual exclusion lock.
-type RWMutex struct {
-	sync.RWMutex
-}
diff --git a/internal/libs/tempfile/tempfile.go b/internal/libs/tempfile/tempfile.go
index 0c594bb20..e30d5a8c6 100644
--- a/internal/libs/tempfile/tempfile.go
+++ b/internal/libs/tempfile/tempfile.go
@@ -7,9 +7,8 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 const (
@@ -32,7 +31,7 @@ const (
 
 var (
 	atomicWriteFileRand   uint64
-	atomicWriteFileRandMu tmsync.Mutex
+	atomicWriteFileRandMu sync.Mutex
 )
 
 func writeFileRandReseed() uint64 {
diff --git a/internal/libs/timer/throttle_timer.go b/internal/libs/timer/throttle_timer.go
index 3f21e3cc0..76db87ee8 100644
--- a/internal/libs/timer/throttle_timer.go
+++ b/internal/libs/timer/throttle_timer.go
@@ -1,9 +1,8 @@
 package timer
 
 import (
+	"sync"
 	"time"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 /*
@@ -18,7 +17,7 @@ type ThrottleTimer struct {
 	quit chan struct{}
 	dur  time.Duration
 
-	mtx   tmsync.Mutex
+	mtx   sync.Mutex
 	timer *time.Timer
 	isSet bool
 }
diff --git a/internal/libs/timer/throttle_timer_test.go b/internal/libs/timer/throttle_timer_test.go
index a56dcadfd..7ea392c3a 100644
--- a/internal/libs/timer/throttle_timer_test.go
+++ b/internal/libs/timer/throttle_timer_test.go
@@ -1,19 +1,18 @@
 package timer
 
 import (
+	"sync"
 	"testing"
 	"time"
 
 	// make govet noshadow happy...
 
 	asrt "github.com/stretchr/testify/assert"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 type thCounter struct {
 	input chan struct{}
-	mtx   tmsync.Mutex
+	mtx   sync.Mutex
 	count int
 }
 
diff --git a/internal/mempool/cache.go b/internal/mempool/cache.go
index 3cd45d2bc..c69fc80dd 100644
--- a/internal/mempool/cache.go
+++ b/internal/mempool/cache.go
@@ -2,8 +2,8 @@ package mempool
 
 import (
 	"container/list"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -29,7 +29,7 @@ var _ TxCache = (*LRUTxCache)(nil)
 // LRUTxCache maintains a thread-safe LRU cache of raw transactions. The cache
 // only stores the hash of the raw transaction.
 type LRUTxCache struct {
-	mtx      tmsync.Mutex
+	mtx      sync.Mutex
 	size     int
 	cacheMap map[types.TxKey]*list.Element
 	list     *list.List
diff --git a/internal/mempool/ids.go b/internal/mempool/ids.go
index 656f5b74c..3788afcbc 100644
--- a/internal/mempool/ids.go
+++ b/internal/mempool/ids.go
@@ -2,13 +2,13 @@ package mempool
 
 import (
 	"fmt"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/types"
 )
 
 type IDs struct {
-	mtx       tmsync.RWMutex
+	mtx       sync.RWMutex
 	peerMap   map[types.NodeID]uint16
 	nextID    uint16              // assumes that a node will never have over 65536 active peers
 	activeIDs map[uint16]struct{} // used to check if a given peerID key is used
diff --git a/internal/mempool/mempool.go b/internal/mempool/mempool.go
index f5d1c926d..82aa3d7c7 100644
--- a/internal/mempool/mempool.go
+++ b/internal/mempool/mempool.go
@@ -6,13 +6,13 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+	"sync"
 	"sync/atomic"
 	"time"
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/internal/libs/clist"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/proxy"
 	"github.com/tendermint/tendermint/libs/log"
 	tmmath "github.com/tendermint/tendermint/libs/math"
@@ -86,7 +86,7 @@ type TxMempool struct {
 	// from the mempool. A read-lock is implicitly acquired when executing CheckTx,
 	// however, a caller must explicitly grab a write-lock via Lock when updating
 	// the mempool via Update().
-	mtx       tmsync.RWMutex
+	mtx       sync.RWMutex
 	preCheck  PreCheckFunc
 	postCheck PostCheckFunc
 }
diff --git a/internal/mempool/priority_queue.go b/internal/mempool/priority_queue.go
index f59715abb..e31997397 100644
--- a/internal/mempool/priority_queue.go
+++ b/internal/mempool/priority_queue.go
@@ -3,15 +3,14 @@ package mempool
 import (
 	"container/heap"
 	"sort"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
+	"sync"
 )
 
 var _ heap.Interface = (*TxPriorityQueue)(nil)
 
 // TxPriorityQueue defines a thread-safe priority queue for valid transactions.
 type TxPriorityQueue struct {
-	mtx tmsync.RWMutex
+	mtx sync.RWMutex
 	txs []*WrappedTx
 }
 
diff --git a/internal/mempool/reactor.go b/internal/mempool/reactor.go
index 7119cdbbb..14b52e917 100644
--- a/internal/mempool/reactor.go
+++ b/internal/mempool/reactor.go
@@ -57,7 +57,7 @@ type Reactor struct {
 	// Reactor. observePanic is called with the recovered value.
 	observePanic func(interface{})
 
-	mtx          tmsync.Mutex
+	mtx          sync.Mutex
 	peerRoutines map[types.NodeID]*tmsync.Closer
 }
 
diff --git a/internal/mempool/tx.go b/internal/mempool/tx.go
index af48c9ccc..c7113c951 100644
--- a/internal/mempool/tx.go
+++ b/internal/mempool/tx.go
@@ -2,10 +2,10 @@ package mempool
 
 import (
 	"sort"
+	"sync"
 	"time"
 
 	"github.com/tendermint/tendermint/internal/libs/clist"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -76,7 +76,7 @@ func (wtx *WrappedTx) Size() int {
 //   access is not allowed. Regardless, it is not expected for the mempool to
 //   need mutative access.
 type TxStore struct {
-	mtx       tmsync.RWMutex
+	mtx       sync.RWMutex
 	hashTxs   map[types.TxKey]*WrappedTx // primary index
 	senderTxs map[string]*WrappedTx      // sender is defined by the ABCI application
 }
@@ -217,7 +217,7 @@ func (txs *TxStore) GetOrSetPeerByTxHash(hash types.TxKey, peerID uint16) (*Wrap
 // references which is used during Insert in order to determine sorted order. If
 // less returns true, a <= b.
 type WrappedTxList struct {
-	mtx  tmsync.RWMutex
+	mtx  sync.RWMutex
 	txs  []*WrappedTx
 	less func(*WrappedTx, *WrappedTx) bool
 }
diff --git a/internal/p2p/conn/connection.go b/internal/p2p/conn/connection.go
index fa21358c1..a51585d3f 100644
--- a/internal/p2p/conn/connection.go
+++ b/internal/p2p/conn/connection.go
@@ -10,6 +10,7 @@ import (
 	"net"
 	"reflect"
 	"runtime/debug"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -17,7 +18,6 @@ import (
 
 	"github.com/tendermint/tendermint/internal/libs/flowrate"
 	"github.com/tendermint/tendermint/internal/libs/protoio"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/libs/timer"
 	"github.com/tendermint/tendermint/libs/log"
 	tmmath "github.com/tendermint/tendermint/libs/math"
@@ -100,7 +100,7 @@ type MConnection struct {
 
 	// used to ensure FlushStop and OnStop
 	// are safe to call concurrently.
-	stopMtx tmsync.Mutex
+	stopMtx sync.Mutex
 
 	cancel context.CancelFunc
 
diff --git a/internal/p2p/conn/secret_connection.go b/internal/p2p/conn/secret_connection.go
index 35fac488a..f67c89e5b 100644
--- a/internal/p2p/conn/secret_connection.go
+++ b/internal/p2p/conn/secret_connection.go
@@ -11,6 +11,7 @@ import (
 	"io"
 	"math"
 	"net"
+	"sync"
 	"time"
 
 	gogotypes "github.com/gogo/protobuf/types"
@@ -25,7 +26,6 @@ import (
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/encoding"
 	"github.com/tendermint/tendermint/internal/libs/protoio"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/async"
 	tmp2p "github.com/tendermint/tendermint/proto/tendermint/p2p"
 )
@@ -76,11 +76,11 @@ type SecretConnection struct {
 	// are independent, so we can use two mtxs.
 	// All .Read are covered by recvMtx,
 	// all .Write are covered by sendMtx.
-	recvMtx    tmsync.Mutex
+	recvMtx    sync.Mutex
 	recvBuffer []byte
 	recvNonce  *[aeadNonceSize]byte
 
-	sendMtx   tmsync.Mutex
+	sendMtx   sync.Mutex
 	sendNonce *[aeadNonceSize]byte
 }
 
diff --git a/internal/statesync/chunks.go b/internal/statesync/chunks.go
index 2075adae5..6f6387637 100644
--- a/internal/statesync/chunks.go
+++ b/internal/statesync/chunks.go
@@ -6,9 +6,9 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"sync"
 	"time"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -28,7 +28,7 @@ type chunk struct {
 // iterator over all chunks, but callers can request chunks to be retried, optionally after
 // refetching.
 type chunkQueue struct {
-	tmsync.Mutex
+	sync.Mutex
 	snapshot       *snapshot                  // if this is nil, the queue has been closed
 	dir            string                     // temp dir for on-disk chunk storage
 	chunkFiles     map[uint32]string          // path to temporary chunk file
diff --git a/internal/statesync/reactor.go b/internal/statesync/reactor.go
index 34281919e..b161225a8 100644
--- a/internal/statesync/reactor.go
+++ b/internal/statesync/reactor.go
@@ -8,11 +8,11 @@ import (
 	"reflect"
 	"runtime/debug"
 	"sort"
+	"sync"
 	"time"
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/config"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/p2p"
 	"github.com/tendermint/tendermint/internal/proxy"
 	sm "github.com/tendermint/tendermint/internal/state"
@@ -151,7 +151,7 @@ type Reactor struct {
 	// These will only be set when a state sync is in progress. It is used to feed
 	// received snapshots and chunks into the syncer and manage incoming and outgoing
 	// providers.
-	mtx           tmsync.RWMutex
+	mtx           sync.RWMutex
 	syncer        *syncer
 	providers     map[types.NodeID]*BlockProvider
 	stateProvider StateProvider
diff --git a/internal/statesync/snapshots.go b/internal/statesync/snapshots.go
index a0620e450..0e3bbb47a 100644
--- a/internal/statesync/snapshots.go
+++ b/internal/statesync/snapshots.go
@@ -6,8 +6,8 @@ import (
 	"math/rand"
 	"sort"
 	"strings"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -41,7 +41,7 @@ func (s *snapshot) Key() snapshotKey {
 
 // snapshotPool discovers and aggregates snapshots across peers.
 type snapshotPool struct {
-	tmsync.Mutex
+	sync.Mutex
 	snapshots     map[snapshotKey]*snapshot
 	snapshotPeers map[snapshotKey]map[types.NodeID]types.NodeID
 
diff --git a/internal/statesync/stateprovider.go b/internal/statesync/stateprovider.go
index 4f398ce77..b798eb9ad 100644
--- a/internal/statesync/stateprovider.go
+++ b/internal/statesync/stateprovider.go
@@ -6,11 +6,11 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"sync"
 	"time"
 
 	dbm "github.com/tendermint/tm-db"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/p2p"
 	sm "github.com/tendermint/tendermint/internal/state"
 	"github.com/tendermint/tendermint/libs/log"
@@ -40,7 +40,7 @@ type StateProvider interface {
 }
 
 type stateProviderRPC struct {
-	tmsync.Mutex  // light.Client is not concurrency-safe
+	sync.Mutex    // light.Client is not concurrency-safe
 	lc            *light.Client
 	initialHeight int64
 	providers     map[lightprovider.Provider]string
@@ -197,7 +197,7 @@ func rpcClient(server string) (*rpchttp.HTTP, error) {
 }
 
 type stateProviderP2P struct {
-	tmsync.Mutex  // light.Client is not concurrency-safe
+	sync.Mutex    // light.Client is not concurrency-safe
 	lc            *light.Client
 	initialHeight int64
 	paramsSendCh  *p2p.Channel
diff --git a/internal/statesync/syncer.go b/internal/statesync/syncer.go
index b5ea158a4..a09d84d9f 100644
--- a/internal/statesync/syncer.go
+++ b/internal/statesync/syncer.go
@@ -5,11 +5,11 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"sync"
 	"time"
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/config"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/p2p"
 	"github.com/tendermint/tendermint/internal/proxy"
 	sm "github.com/tendermint/tendermint/internal/state"
@@ -63,7 +63,7 @@ type syncer struct {
 	fetchers      int32
 	retryTimeout  time.Duration
 
-	mtx     tmsync.RWMutex
+	mtx     sync.RWMutex
 	chunks  *chunkQueue
 	metrics *Metrics
 
diff --git a/internal/statesync/syncer_test.go b/internal/statesync/syncer_test.go
index bd4640fe0..2e8556f68 100644
--- a/internal/statesync/syncer_test.go
+++ b/internal/statesync/syncer_test.go
@@ -12,7 +12,6 @@ import (
 	"github.com/stretchr/testify/require"
 
 	abci "github.com/tendermint/tendermint/abci/types"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/internal/proxy"
 	proxymocks "github.com/tendermint/tendermint/internal/proxy/mocks"
 	sm "github.com/tendermint/tendermint/internal/state"
@@ -132,7 +131,7 @@ func TestSyncer_SyncAny(t *testing.T) {
 	}).Times(2).Return(&abci.ResponseOfferSnapshot{Result: abci.ResponseOfferSnapshot_ACCEPT}, nil)
 
 	chunkRequests := make(map[uint32]int)
-	chunkRequestsMtx := tmsync.Mutex{}
+	chunkRequestsMtx := sync.Mutex{}
 
 	var wg sync.WaitGroup
 	wg.Add(4)
diff --git a/libs/events/events.go b/libs/events/events.go
index 29ebd672f..b5b6f76df 100644
--- a/libs/events/events.go
+++ b/libs/events/events.go
@@ -4,8 +4,8 @@ package events
 import (
 	"context"
 	"fmt"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -56,7 +56,7 @@ type EventSwitch interface {
 type eventSwitch struct {
 	service.BaseService
 
-	mtx        tmsync.RWMutex
+	mtx        sync.RWMutex
 	eventCells map[string]*eventCell
 	listeners  map[string]*eventListener
 }
@@ -166,7 +166,7 @@ func (evsw *eventSwitch) FireEvent(ctx context.Context, event string, data Event
 
 // eventCell handles keeping track of listener callbacks for a given event.
 type eventCell struct {
-	mtx       tmsync.RWMutex
+	mtx       sync.RWMutex
 	listeners map[string]EventCallback
 }
 
@@ -213,7 +213,7 @@ type EventCallback func(ctx context.Context, data EventData) error
 type eventListener struct {
 	id string
 
-	mtx     tmsync.RWMutex
+	mtx     sync.RWMutex
 	removed bool
 	events  []string
 }
diff --git a/libs/json/structs.go b/libs/json/structs.go
index b9521114a..b20873c33 100644
--- a/libs/json/structs.go
+++ b/libs/json/structs.go
@@ -4,9 +4,8 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
+	"sync"
 	"unicode"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 )
 
 var (
@@ -16,7 +15,7 @@ var (
 
 // structCache is a cache of struct info.
 type structInfoCache struct {
-	tmsync.RWMutex
+	sync.RWMutex
 	structInfos map[reflect.Type]*structInfo
 }
 
diff --git a/libs/json/types.go b/libs/json/types.go
index 9f21e81eb..9c9493056 100644
--- a/libs/json/types.go
+++ b/libs/json/types.go
@@ -4,8 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
+	"sync"
 )
 
 var (
@@ -39,7 +38,7 @@ type typeInfo struct {
 
 // types is a type registry. It is safe for concurrent use.
 type types struct {
-	tmsync.RWMutex
+	sync.RWMutex
 	byType map[reflect.Type]*typeInfo
 	byName map[string]*typeInfo
 }
diff --git a/light/client.go b/light/client.go
index 866de7627..99a44f498 100644
--- a/light/client.go
+++ b/light/client.go
@@ -9,7 +9,6 @@ import (
 	"sync"
 	"time"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/light/provider"
@@ -134,7 +133,7 @@ type Client struct {
 	providerTimeout  time.Duration
 
 	// Mutex for locking during changes of the light clients providers
-	providerMutex tmsync.Mutex
+	providerMutex sync.Mutex
 	// Primary provider of new headers.
 	primary provider.Provider
 	// Providers used to "witness" new headers.
diff --git a/light/store/db/db.go b/light/store/db/db.go
index acfda1f79..c364e1709 100644
--- a/light/store/db/db.go
+++ b/light/store/db/db.go
@@ -3,11 +3,11 @@ package db
 import (
 	"encoding/binary"
 	"fmt"
+	"sync"
 
 	"github.com/google/orderedcode"
 	dbm "github.com/tendermint/tm-db"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/light/store"
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 	"github.com/tendermint/tendermint/types"
@@ -21,7 +21,7 @@ const (
 type dbs struct {
 	db dbm.DB
 
-	mtx  tmsync.RWMutex
+	mtx  sync.RWMutex
 	size uint16
 }
 
diff --git a/privval/secret_connection.go b/privval/secret_connection.go
index ffa5d36ed..9192c3114 100644
--- a/privval/secret_connection.go
+++ b/privval/secret_connection.go
@@ -11,6 +11,7 @@ import (
 	"io"
 	"math"
 	"net"
+	"sync"
 	"time"
 
 	gogotypes "github.com/gogo/protobuf/types"
@@ -25,7 +26,6 @@ import (
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/encoding"
 	"github.com/tendermint/tendermint/internal/libs/protoio"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/async"
 	tmprivval "github.com/tendermint/tendermint/proto/tendermint/privval"
 )
@@ -80,11 +80,11 @@ type SecretConnection struct {
 	// are independent, so we can use two mtxs.
 	// All .Read are covered by recvMtx,
 	// all .Write are covered by sendMtx.
-	recvMtx    tmsync.Mutex
+	recvMtx    sync.Mutex
 	recvBuffer []byte
 	recvNonce  *[aeadNonceSize]byte
 
-	sendMtx   tmsync.Mutex
+	sendMtx   sync.Mutex
 	sendNonce *[aeadNonceSize]byte
 }
 
diff --git a/privval/signer_endpoint.go b/privval/signer_endpoint.go
index b48e79f94..5cf4f7be7 100644
--- a/privval/signer_endpoint.go
+++ b/privval/signer_endpoint.go
@@ -3,10 +3,10 @@ package privval
 import (
 	"fmt"
 	"net"
+	"sync"
 	"time"
 
 	"github.com/tendermint/tendermint/internal/libs/protoio"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 	privvalproto "github.com/tendermint/tendermint/proto/tendermint/privval"
@@ -20,7 +20,7 @@ type signerEndpoint struct {
 	service.BaseService
 	logger log.Logger
 
-	connMtx tmsync.Mutex
+	connMtx sync.Mutex
 	conn    net.Conn
 
 	timeoutReadWrite time.Duration
diff --git a/privval/signer_listener_endpoint.go b/privval/signer_listener_endpoint.go
index 15622925d..ff2c0b7c2 100644
--- a/privval/signer_listener_endpoint.go
+++ b/privval/signer_listener_endpoint.go
@@ -4,9 +4,9 @@ import (
 	"context"
 	"fmt"
 	"net"
+	"sync"
 	"time"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 	privvalproto "github.com/tendermint/tendermint/proto/tendermint/privval"
@@ -39,7 +39,7 @@ type SignerListenerEndpoint struct {
 	pingTimer     *time.Ticker
 	pingInterval  time.Duration
 
-	instanceMtx tmsync.Mutex // Ensures instance public methods access, i.e. SendRequest
+	instanceMtx sync.Mutex // Ensures instance public methods access, i.e. SendRequest
 }
 
 // NewSignerListenerEndpoint returns an instance of SignerListenerEndpoint.
diff --git a/privval/signer_server.go b/privval/signer_server.go
index 4c4d6282a..e1235d5f3 100644
--- a/privval/signer_server.go
+++ b/privval/signer_server.go
@@ -3,8 +3,8 @@ package privval
 import (
 	"context"
 	"io"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/service"
 	privvalproto "github.com/tendermint/tendermint/proto/tendermint/privval"
 	"github.com/tendermint/tendermint/types"
@@ -24,7 +24,7 @@ type SignerServer struct {
 	chainID  string
 	privVal  types.PrivValidator
 
-	handlerMtx               tmsync.Mutex
+	handlerMtx               sync.Mutex
 	validationRequestHandler ValidationRequestHandlerFunc
 }
 
diff --git a/rpc/client/http/ws.go b/rpc/client/http/ws.go
index dda8e4f46..320540450 100644
--- a/rpc/client/http/ws.go
+++ b/rpc/client/http/ws.go
@@ -5,9 +5,9 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"sync"
 	"time"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	tmjson "github.com/tendermint/tendermint/libs/json"
 	"github.com/tendermint/tendermint/libs/pubsub"
 	rpcclient "github.com/tendermint/tendermint/rpc/client"
@@ -48,7 +48,7 @@ type wsEvents struct {
 	*rpcclient.RunState
 	ws *jsonrpcclient.WSClient
 
-	mtx           tmsync.RWMutex
+	mtx           sync.RWMutex
 	subscriptions map[string]*wsSubscription
 }
 
diff --git a/rpc/jsonrpc/client/http_json_client.go b/rpc/jsonrpc/client/http_json_client.go
index 03fc19be4..45f516f04 100644
--- a/rpc/jsonrpc/client/http_json_client.go
+++ b/rpc/jsonrpc/client/http_json_client.go
@@ -11,9 +11,9 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 	"time"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
 )
 
@@ -130,7 +130,7 @@ type Client struct {
 
 	client *http.Client
 
-	mtx       tmsync.Mutex
+	mtx       sync.Mutex
 	nextReqID int
 }
 
@@ -304,7 +304,7 @@ type jsonRPCBufferedRequest struct {
 type RequestBatch struct {
 	client *Client
 
-	mtx      tmsync.Mutex
+	mtx      sync.Mutex
 	requests []*jsonRPCBufferedRequest
 }
 
diff --git a/rpc/jsonrpc/client/ws_client.go b/rpc/jsonrpc/client/ws_client.go
index 51891712f..98cff05ce 100644
--- a/rpc/jsonrpc/client/ws_client.go
+++ b/rpc/jsonrpc/client/ws_client.go
@@ -13,7 +13,6 @@ import (
 	"github.com/gorilla/websocket"
 	metrics "github.com/rcrowley/go-metrics"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	tmclient "github.com/tendermint/tendermint/rpc/client"
 	rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
 )
@@ -70,7 +69,7 @@ type WSClient struct { // nolint: maligned
 
 	wg sync.WaitGroup
 
-	mtx            tmsync.RWMutex
+	mtx            sync.RWMutex
 	sentLastPingAt time.Time
 	reconnecting   bool
 	nextReqID      int
diff --git a/rpc/jsonrpc/client/ws_client_test.go b/rpc/jsonrpc/client/ws_client_test.go
index d1d6c1fed..9cc65a758 100644
--- a/rpc/jsonrpc/client/ws_client_test.go
+++ b/rpc/jsonrpc/client/ws_client_test.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"runtime"
+	"sync"
 	"testing"
 	"time"
 
@@ -13,7 +14,6 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/stretchr/testify/require"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/log"
 	rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
 )
@@ -22,7 +22,7 @@ var wsCallTimeout = 5 * time.Second
 
 type myHandler struct {
 	closeConnAfterRead bool
-	mtx                tmsync.RWMutex
+	mtx                sync.RWMutex
 }
 
 var upgrader = websocket.Upgrader{
diff --git a/types/block.go b/types/block.go
index 2f444be74..89054e100 100644
--- a/types/block.go
+++ b/types/block.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/gogo/protobuf/proto"
@@ -13,7 +14,6 @@ import (
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/merkle"
 	"github.com/tendermint/tendermint/crypto/tmhash"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/bits"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	tmmath "github.com/tendermint/tendermint/libs/math"
@@ -40,7 +40,7 @@ const (
 
 // Block defines the atomic unit of a Tendermint blockchain.
 type Block struct {
-	mtx tmsync.Mutex
+	mtx sync.Mutex
 
 	Header     `json:"header"`
 	Data       `json:"data"`
diff --git a/types/part_set.go b/types/part_set.go
index 3a691083f..9699f2b32 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -5,9 +5,9 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sync"
 
 	"github.com/tendermint/tendermint/crypto/merkle"
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/bits"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	tmjson "github.com/tendermint/tendermint/libs/json"
@@ -151,7 +151,7 @@ type PartSet struct {
 	total uint32
 	hash  []byte
 
-	mtx           tmsync.Mutex
+	mtx           sync.Mutex
 	parts         []*Part
 	partsBitArray *bits.BitArray
 	count         uint32
diff --git a/types/vote_set.go b/types/vote_set.go
index e014ae7bb..46e6d270d 100644
--- a/types/vote_set.go
+++ b/types/vote_set.go
@@ -4,8 +4,8 @@ import (
 	"bytes"
 	"fmt"
 	"strings"
+	"sync"
 
-	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
 	"github.com/tendermint/tendermint/libs/bits"
 	tmjson "github.com/tendermint/tendermint/libs/json"
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
@@ -65,7 +65,7 @@ type VoteSet struct {
 	signedMsgType tmproto.SignedMsgType
 	valSet        *ValidatorSet
 
-	mtx           tmsync.Mutex
+	mtx           sync.Mutex
 	votesBitArray *bits.BitArray
 	votes         []*Vote                // Primary votes to share
 	sum           int64                  // Sum of voting power for seen votes, discounting conflicts