About STM8S003 be reset continoustly

[qloi]

Hello everyone, I have got a problem but I can't resolve it.

I made a project read NMEA string from UART and show it to OLED 128x64 (I2C interface) with STM8s003F3P6. everything is OK when I tried to get GPS strings from UART and store them variable , with OLED also ok and I can show everything on it . But when I combine 2 libs(GPS parsing and OLED disp) I got very strange thing!. After power on, the circuit show all GPS data I need , it run few seconds and auto reset STM chip, all is restart and repeated same way?

I can't find where error, maybe stack overflow?

the code flow follow:

UART_ISR()
 
{
 newdata = get_GPS_data(); //get NMEA string , when get all, newdata = 1
}
 
 
 
main()
{
 while(1)
 {
 if(newdata)
 {
 newdata = 0;
 pro = GPS_parse(); //parsing GPS data and storge into variable
 If(pro) //handled afer 2 sec (the UART received NMEA 2s period)
 {
 //pro = 0;
 _disable_interrupt();
 OLED_show(); //show data on OLED
 _enable_interrupt();
 }
 }
}

please help!