ebpf: sending data from userspace and waiting for that

I'm using ebpf and bcc to write an ebpf-lsm program. I want to block a connected USB device and send its info to userspace and the user send me whether I bind that device or no. how can I do this? I know using ebpf maps we can receive data from userspace, well how can I wait for that? in another word, how can I block ebpf program until user responses? thank you for any guidness!