diff --git a/gnet_test.go b/gnet_test.go
index 22eae807b..abf5ee569 100644
--- a/gnet_test.go
+++ b/gnet_test.go
@@ -17,6 +17,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap"
+	"golang.org/x/sync/errgroup"
 
 	gerr "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
@@ -1135,6 +1136,33 @@ func (s *testClosedWakeUpServer) OnClose(Conn, error) (action Action) {
 	return
 }
 
+type testMultiInstLoggerRaceServer struct {
+	*BuiltinEventEngine
+}
+
+func (t *testMultiInstLoggerRaceServer) OnBoot(_ Engine) (action Action) {
+	return Shutdown
+}
+
+func TestMultiInstLoggerRace(t *testing.T) {
+	logger1, _ := zap.NewDevelopment()
+	events1 := new(testMultiInstLoggerRaceServer)
+	g := errgroup.Group{}
+	g.Go(func() error {
+		err := Run(events1, "tulip://howdy", WithLogger(logger1.Sugar()))
+		return err
+	})
+
+	logger2, _ := zap.NewDevelopment()
+	events2 := new(testMultiInstLoggerRaceServer)
+	g.Go(func() error {
+		err := Run(events2, "tulip://howdy", WithLogger(logger2.Sugar()))
+		return err
+	})
+
+	assert.ErrorIs(t, g.Wait(), gerr.ErrUnsupportedProtocol)
+}
+
 var errIncompletePacket = errors.New("incomplete packet")
 
 type simServer struct {
diff --git a/go.mod b/go.mod
index 69962a960..f47d80576 100644
--- a/go.mod
+++ b/go.mod
@@ -1,7 +1,7 @@
 module github.com/panjf2000/gnet/v2
 
 require (
-	github.com/panjf2000/ants/v2 v2.7.4
+	github.com/panjf2000/ants/v2 v2.8.1
 	github.com/stretchr/testify v1.8.2
 	github.com/valyala/bytebufferpool v1.0.0
 	go.uber.org/zap v1.21.0
diff --git a/go.sum b/go.sum
index a1055fd27..f10e6e250 100644
--- a/go.sum
+++ b/go.sum
@@ -8,8 +8,8 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/panjf2000/ants/v2 v2.7.4 h1:mJqMDtMckZltyL458pq81IGNfiDhEgzX5s/lhjwPWIM=
-github.com/panjf2000/ants/v2 v2.7.4/go.mod h1:KIBmYG9QQX5U2qzFP/yQJaq/nSb6rahS9iEHkrCMgM8=
+github.com/panjf2000/ants/v2 v2.8.1 h1:C+n/f++aiW8kHCExKlpX6X+okmxKXP7DWLutxuAPuwQ=
+github.com/panjf2000/ants/v2 v2.8.1/go.mod h1:KIBmYG9QQX5U2qzFP/yQJaq/nSb6rahS9iEHkrCMgM8=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
diff --git a/pkg/logging/logger.go b/pkg/logging/logger.go
index 784aba2ec..86ad17e93 100644
--- a/pkg/logging/logger.go
+++ b/pkg/logging/logger.go
@@ -50,6 +50,7 @@ import (
 	"errors"
 	"os"
 	"strconv"
+	"strings"
 	"sync"
 
 	"go.uber.org/zap"
@@ -63,6 +64,7 @@ import (
 type Flusher = func() error
 
 var (
+	mu                  sync.RWMutex
 	defaultLogger       Logger
 	defaultLoggingLevel Level
 	defaultFlusher      Flusher
@@ -171,30 +173,28 @@ func getProdEncoder() zapcore.Encoder {
 
 // GetDefaultLogger returns the default logger.
 func GetDefaultLogger() Logger {
+	mu.RLock()
+	defer mu.RUnlock()
 	return defaultLogger
 }
 
 // GetDefaultFlusher returns the default flusher.
 func GetDefaultFlusher() Flusher {
+	mu.RLock()
+	defer mu.RUnlock()
 	return defaultFlusher
 }
 
-var setupOnce sync.Once
-
 // SetDefaultLoggerAndFlusher sets the default logger and its flusher.
-//
-// Note that this function should only be called once at the
-// start of the program and not thereafter for the entire runtime,
-// otherwise it will only keep the first setup.
 func SetDefaultLoggerAndFlusher(logger Logger, flusher Flusher) {
-	setupOnce.Do(func() {
-		defaultLogger, defaultFlusher = logger, flusher
-	})
+	mu.Lock()
+	defaultLogger, defaultFlusher = logger, flusher
+	mu.Unlock()
 }
 
 // LogLevel tells what the default logging level is.
 func LogLevel() string {
-	return defaultLoggingLevel.String()
+	return strings.ToUpper(defaultLoggingLevel.String())
 }
 
 // CreateLoggerAsLocalFile setups the logger by local file path.
@@ -227,41 +227,55 @@ func CreateLoggerAsLocalFile(localFilePath string, logLevel Level) (logger Logge
 
 // Cleanup does something windup for logger, like closing, flushing, etc.
 func Cleanup() {
+	mu.RLock()
 	if defaultFlusher != nil {
 		_ = defaultFlusher()
 	}
+	mu.RUnlock()
 }
 
 // Error prints err if it's not nil.
 func Error(err error) {
 	if err != nil {
+		mu.RLock()
 		defaultLogger.Errorf("error occurs during runtime, %v", err)
+		mu.RUnlock()
 	}
 }
 
 // Debugf logs messages at DEBUG level.
 func Debugf(format string, args ...interface{}) {
+	mu.RLock()
 	defaultLogger.Debugf(format, args...)
+	mu.RUnlock()
 }
 
 // Infof logs messages at INFO level.
 func Infof(format string, args ...interface{}) {
+	mu.RLock()
 	defaultLogger.Infof(format, args...)
+	mu.RUnlock()
 }
 
 // Warnf logs messages at WARN level.
 func Warnf(format string, args ...interface{}) {
+	mu.RLock()
 	defaultLogger.Warnf(format, args...)
+	mu.RUnlock()
 }
 
 // Errorf logs messages at ERROR level.
 func Errorf(format string, args ...interface{}) {
+	mu.RLock()
 	defaultLogger.Errorf(format, args...)
+	mu.RUnlock()
 }
 
 // Fatalf logs messages at FATAL level.
 func Fatalf(format string, args ...interface{}) {
+	mu.RLock()
 	defaultLogger.Fatalf(format, args...)
+	mu.RUnlock()
 }
 
 // Logger is used for logging formatted messages.