Note that "0x8000001" indicates "tty01" of machine A, majar device number is 8 and minor is 1.makeoptions DEBUG="-g" options DEBUG options KGDB options "KGDBDEV=0x800001"
It would be very useful if you run "gdb" on Emacs.gdb -k bsd.gdb
target remote /dev/tty00
Now the kernel on machine A is suspended.