Will it stop if your cut it off or unplug the washer. If not, your water inlet valve is stuck.

If it does your water level switch may be bad. Part 10 in this diagram of your control panel. The Tube going to it may be stopped up.

Just fixed my GE top loader this morning. Would not stop adding water until it ran over. Stopped when off button was pressed. Checked the pressure regulator air line and, like the man said, it was clogged with some kind of gunk. Flushed with vinegar, washed that crap out, dried the hose and she works good as new. Water stops at each level from small to extra lg. Easiest repair imaginable and cost nothing! Your tip save me money and aggravation.