无法将串行数据读取到tkinter GUI

import tkinter as tk
import serial
import threading

class SerialReader:
    def __init__(self, port, baudrate):
        self.serial = serial.Serial(port, baudrate)
        self.running = False

    def read_data(self):
        while self.running:
            if self.serial.in_waiting > 0:
                data = self.serial.readline().decode('utf-8').strip()
                self.data_callback(data)

    def start(self, callback):
        self.data_callback = callback
        self.running = True
        threading.Thread(target=self.read_data).start()

    def stop(self):
        self.running = False

class App:
    def __init__(self, root):
        self.root = root
        self.label = tk.Label(root, text="Serial Data:")
        self.label.pack()
        self.text = tk.Text(root, height=10, width=50)
        self.text.pack()
        self.reader = SerialReader('/dev/ttyUSB0', 9600)
        self.reader.start(self.update_text)

    def update_text(self, data):
        self.text.insert(tk.END, data + "\n")

    def on_close(self):
        self.reader.stop()
        self.root.destroy()

if __name__ == "__main__":
    root = tk.Tk()
    app = App(root)
    root.protocol("WM_DELETE_WINDOW", app.on_close)
    root.mainloop()