Deadlock concurrency in golang

.go

package main

import "fmt"

var (
	first  chan string
	second chan string
)

func main() {
	go forever()
	second <- "From main"
}

func forever() {
	for {
		select {
		case f := <-first:
			fmt.Println(f)
		case s := <-second:
			block(s)
		}
	}
}

func block(str string) {
	first <- "From block function " + str
}