@ChrisW67
Thank you for you help.
Probably the thing is, QSerialPort has a problem to work in a new thread.
I can handle the other QObject in a new thread very well, and the exception only happens when the Object contains QSerialPort.
Also, in my last post, I actually never user QList, although Qt tells me something wrong with QList.
I have given up on working serialThread. QSerialPort does work good in the main thread.