when I use kgdb debugging kernel, I have added the "kgdbwait" to the kernel boot options, bug the system can't stop at booting for my gdb to connect

when I use kgdb debugging kernel, I have added the "kgdbwait" to the kernel boot options, bug the system can't stop at booting for my gdb to connect In gdb session , type continue . It outputs "The program is not run"