diff --git a/connection.go b/connection.go
index c70c59d..a6b27a0 100644
--- a/connection.go
+++ b/connection.go
@@ -490,6 +490,7 @@ func (u *gettyUDPConn) CloseConn(_ int) {
 type gettyWSConn struct {
 	gettyConn
 	conn *websocket.Conn
+	lock sync.Mutex
 }
 
 // create websocket connection
@@ -608,7 +609,7 @@ func (w *gettyWSConn) Send(pkg interface{}) (int, error) {
 	}
 
 	w.updateWriteDeadline()
-	if err = w.conn.WriteMessage(websocket.BinaryMessage, p); err == nil {
+	if err = w.threadSafeWriteMessage(websocket.BinaryMessage, p); err == nil {
 		w.writeBytes.Add((uint32)(len(p)))
 		w.writePkgNum.Add(1)
 	}
@@ -617,18 +618,18 @@ func (w *gettyWSConn) Send(pkg interface{}) (int, error) {
 
 func (w *gettyWSConn) writePing() error {
 	w.updateWriteDeadline()
-	return perrors.WithStack(w.conn.WriteMessage(websocket.PingMessage, []byte{}))
+	return perrors.WithStack(w.threadSafeWriteMessage(websocket.PingMessage, []byte{}))
 }
 
 func (w *gettyWSConn) writePong(message []byte) error {
 	w.updateWriteDeadline()
-	return perrors.WithStack(w.conn.WriteMessage(websocket.PongMessage, message))
+	return perrors.WithStack(w.threadSafeWriteMessage(websocket.PongMessage, message))
 }
 
 // close websocket connection
 func (w *gettyWSConn) CloseConn(waitSec int) {
 	w.updateWriteDeadline()
-	w.conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, "bye-bye!!!"))
+	w.threadSafeWriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, "bye-bye!!!"))
 	conn := w.conn.UnderlyingConn()
 	if tcpConn, ok := conn.(*net.TCPConn); ok {
 		tcpConn.SetLinger(waitSec)
@@ -637,3 +638,13 @@ func (w *gettyWSConn) CloseConn(waitSec int) {
 	}
 	w.conn.Close()
 }
+
+// uses a mutex to ensure that only one thread can send a message at a time, preventing race conditions.
+func (w *gettyWSConn) threadSafeWriteMessage(messageType int, data []byte) error {
+	w.lock.Lock()
+	defer w.lock.Unlock()
+	if err := w.conn.WriteMessage(messageType, data); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/session.go b/session.go
index 587f654..7e704b5 100644
--- a/session.go
+++ b/session.go
@@ -368,7 +368,7 @@ func (s *session) sessionToken() string {
 		s.name, s.EndPoint().EndPointType(), s.ID(), s.LocalAddr(), s.RemoteAddr())
 }
 
-func (s *session) WritePkg(pkg interface{}, timeout time.Duration) (int, int, error) {
+func (s *session) WritePkg(pkg interface{}, timeout time.Duration) (pkgBytesLenth int, successCount int, err error) {
 	if pkg == nil {
 		return 0, 0, fmt.Errorf("@pkg is nil")
 	}
@@ -381,7 +381,8 @@ func (s *session) WritePkg(pkg interface{}, timeout time.Duration) (int, int, er
 			const size = 64 << 10
 			rBuf := make([]byte, size)
 			rBuf = rBuf[:runtime.Stack(rBuf, false)]
-			log.Errorf("[session.WritePkg] panic session %s: err=%s\n%s", s.sessionToken(), r, rBuf)
+			err = perrors.WithStack(fmt.Errorf("[session.WritePkg] panic session %s: err=%v\n%s", s.sessionToken(), r, rBuf))
+			log.Error(err)
 		}
 	}()
 
@@ -407,13 +408,12 @@ func (s *session) WritePkg(pkg interface{}, timeout time.Duration) (int, int, er
 	if 0 < timeout {
 		s.Connection.SetWriteTimeout(timeout)
 	}
-	var succssCount int
-	succssCount, err = s.Connection.Send(pkg)
+	successCount, err = s.Connection.Send(pkg)
 	if err != nil {
 		log.Warnf("%s, [session.WritePkg] @s.Connection.Write(pkg:%#v) = err:%+v", s.Stat(), pkg, err)
-		return len(pkgBytes), succssCount, perrors.WithStack(err)
+		return len(pkgBytes), successCount, perrors.WithStack(err)
 	}
-	return len(pkgBytes), succssCount, nil
+	return len(pkgBytes), successCount, nil
 }
 
 // WriteBytes for codecs