diff --git a/ddl/ddl.go b/ddl/ddl.go
index 86d0c144045c8..c7476b816a4c0 100644
--- a/ddl/ddl.go
+++ b/ddl/ddl.go
@@ -310,6 +310,7 @@ type limitJobTask struct {
 type ddl struct {
 	m          sync.RWMutex
 	quitCh     chan struct{}
+	wg         sync.WaitGroup // It's only used to deal with data race in state_test and schema_test.
 	limitJobCh chan *limitJobTask
 
 	*ddlCtx
@@ -456,13 +457,17 @@ func (d *ddl) start(ctx context.Context, ctxPool *pools.ResourcePool) {
 	logutil.BgLogger().Info("[ddl] start DDL", zap.String("ID", d.uuid), zap.Bool("runWorker", RunWorker))
 	d.quitCh = make(chan struct{})
 
-	go tidbutil.WithRecovery(
-		func() { d.limitDDLJobs() },
-		func(r interface{}) {
-			logutil.BgLogger().Error("[ddl] limit DDL jobs meet panic",
-				zap.String("ID", d.uuid), zap.Reflect("r", r), zap.Stack("stack trace"))
-			metrics.PanicCounter.WithLabelValues(metrics.LabelDDL).Inc()
-		})
+	d.wg.Add(1)
+	go func() {
+		defer d.wg.Done()
+		tidbutil.WithRecovery(
+			func() { d.limitDDLJobs() },
+			func(r interface{}) {
+				logutil.BgLogger().Error("[ddl] limit DDL jobs meet panic",
+					zap.String("ID", d.uuid), zap.Reflect("r", r), zap.Stack("stack trace"))
+				metrics.PanicCounter.WithLabelValues(metrics.LabelDDL).Inc()
+			})
+	}()
 
 	// If RunWorker is true, we need campaign owner and do DDL job.
 	// Otherwise, we needn't do that.
@@ -513,6 +518,7 @@ func (d *ddl) close() {
 
 	startTime := time.Now()
 	close(d.quitCh)
+	d.wg.Wait()
 	d.ownerManager.Cancel()
 	d.schemaSyncer.CloseCleanWork()
 	err := d.schemaSyncer.RemoveSelfVersionPath()
diff --git a/ddl/ddl_test.go b/ddl/ddl_test.go
index d39db842f5c3d..64e67bcfb8065 100644
--- a/ddl/ddl_test.go
+++ b/ddl/ddl_test.go
@@ -71,13 +71,18 @@ func (d *ddl) generalWorker() *worker {
 // It only starts the original workers.
 func (d *ddl) restartWorkers(ctx context.Context) {
 	d.quitCh = make(chan struct{})
-	go util.WithRecovery(
-		func() { d.limitDDLJobs() },
-		func(r interface{}) {
-			logutil.BgLogger().Error("[ddl] DDL add batch DDL jobs meet panic",
-				zap.String("ID", d.uuid), zap.Reflect("r", r), zap.Stack("stack trace"))
-			metrics.PanicCounter.WithLabelValues(metrics.LabelDDL).Inc()
-		})
+
+	d.wg.Add(1)
+	go func() {
+		defer d.wg.Done()
+		util.WithRecovery(
+			func() { d.limitDDLJobs() },
+			func(r interface{}) {
+				logutil.BgLogger().Error("[ddl] DDL add batch DDL jobs meet panic",
+					zap.String("ID", d.uuid), zap.Reflect("r", r), zap.Stack("stack trace"))
+				metrics.PanicCounter.WithLabelValues(metrics.LabelDDL).Inc()
+			})
+	}()
 	if !RunWorker {
 		return
 	}
diff --git a/ddl/reorg_test.go b/ddl/reorg_test.go
index 3bd4edc7f3e81..9f84b5e5389a5 100644
--- a/ddl/reorg_test.go
+++ b/ddl/reorg_test.go
@@ -116,18 +116,6 @@ func (s *testDDLSuite) TestReorg(c *C) {
 	}
 	c.Assert(err, IsNil)
 
-	d.Stop()
-	err = d.generalWorker().runReorgJob(m, rInfo, nil, d.lease, func() error {
-		time.Sleep(4 * testLease)
-		return nil
-	})
-	c.Assert(err, NotNil)
-	txn, err = ctx.Txn(true)
-	c.Assert(err, IsNil)
-	err = txn.Commit(context.Background())
-	c.Assert(err, IsNil)
-
-	d.start(context.Background(), nil)
 	job = &model.Job{
 		ID:          2,
 		SchemaID:    1,
@@ -157,6 +145,17 @@ func (s *testDDLSuite) TestReorg(c *C) {
 		return nil
 	})
 	c.Assert(err, IsNil)
+
+	d.Stop()
+	err = d.generalWorker().runReorgJob(m, rInfo, nil, d.lease, func() error {
+		time.Sleep(4 * testLease)
+		return nil
+	})
+	c.Assert(err, NotNil)
+	txn, err = ctx.Txn(true)
+	c.Assert(err, IsNil)
+	err = txn.Commit(context.Background())
+	c.Assert(err, IsNil)
 }
 
 func (s *testDDLSuite) TestReorgOwner(c *C) {
diff --git a/ddl/schema_test.go b/ddl/schema_test.go
index b9c2485a08189..9cea3ec0b7e97 100644
--- a/ddl/schema_test.go
+++ b/ddl/schema_test.go
@@ -226,6 +226,7 @@ func (s *testSchemaSuite) TestSchemaWaitJob(c *C) {
 func testRunInterruptedJob(c *C, d *ddl, job *model.Job) {
 	ctx := mock.NewContext()
 	ctx.Store = d.store
+
 	done := make(chan error, 1)
 	go func() {
 		done <- d.doDDLJob(ctx, job)
@@ -233,7 +234,6 @@ func testRunInterruptedJob(c *C, d *ddl, job *model.Job) {
 
 	ticker := time.NewTicker(d.lease * 1)
 	defer ticker.Stop()
-
 LOOP:
 	for {
 		select {
diff --git a/ddl/stat_test.go b/ddl/stat_test.go
index 37a60d8a8df72..0bb6b18b6e56a 100644
--- a/ddl/stat_test.go
+++ b/ddl/stat_test.go
@@ -51,8 +51,6 @@ func (s *testStatSuite) TestStat(c *C) {
 	)
 	defer d.Stop()
 
-	time.Sleep(testLease)
-
 	dbInfo := testSchemaInfo(c, d, "test")
 	testCreateSchema(c, testNewContext(d), d, dbInfo)
 
@@ -77,13 +75,12 @@ func (s *testStatSuite) TestStat(c *C) {
 
 	ticker := time.NewTicker(d.lease * 1)
 	defer ticker.Stop()
-
 	ver := s.getDDLSchemaVer(c, d)
 LOOP:
 	for {
 		select {
 		case <-ticker.C:
-			d.close()
+			d.Stop()
 			c.Assert(s.getDDLSchemaVer(c, d), GreaterEqual, ver)
 			d.restartWorkers(context.Background())
 			time.Sleep(time.Millisecond * 20)
diff --git a/executor/seqtest/seq_executor_test.go b/executor/seqtest/seq_executor_test.go
index 5b172ab733461..50f9402ca51d3 100644
--- a/executor/seqtest/seq_executor_test.go
+++ b/executor/seqtest/seq_executor_test.go
@@ -1340,7 +1340,7 @@ func (s *testOOMSuite) TearDownSuite(c *C) {
 func (s *testOOMSuite) registerHook() {
 	conf := &log.Config{Level: os.Getenv("log_level"), File: log.FileLogConfig{}}
 	_, r, _ := log.InitLogger(conf)
-	s.oom = &oomCapturer{r.Core, ""}
+	s.oom = &oomCapturer{r.Core, "", sync.Mutex{}}
 	lg := zap.New(s.oom)
 	log.ReplaceGlobals(lg, r)
 }
@@ -1483,6 +1483,7 @@ func (s *testOOMSuite) TestMemTracker4DeleteExec(c *C) {
 type oomCapturer struct {
 	zapcore.Core
 	tracker string
+	mu      sync.Mutex
 }
 
 func (h *oomCapturer) Write(entry zapcore.Entry, fields []zapcore.Field) error {
@@ -1500,7 +1501,10 @@ func (h *oomCapturer) Write(entry zapcore.Entry, fields []zapcore.Field) error {
 		h.tracker = str[begin+len("8001]") : end]
 		return nil
 	}
+
+	h.mu.Lock()
 	h.tracker = entry.Message
+	h.mu.Unlock()
 	return nil
 }