When the board is connected ONTs, the ONTs respond to the management messages or PLOAM messages sent by the OLT. By reporting interruptions, the board GMAC instructs the CPU to process these messages. The CPLD codes of the GPBD board have a bug. As a result, useless interruptions will be reported to the CPU and the CPU always responds to these interruptions. When the system TICK interruption is generated (once 10 ms), the interruption that cannot be processed in time will be buffered in the system workQ queue. This process repeats. After the queue overflows (the depth of the workQ queue is 64), the operating system automatically resets the board.