How to make lock-free go struct thread-safe

thread_safe_struct.go

package main

import (
	"github.com/AlekSi/pointer"
	log "github.com/sirupsen/logrus"
	"sync"
	"sync/atomic"
	"unsafe"
)

type A struct {
	B int64
	C string
	D *string
}

var globalA unsafe.Pointer

func main() {
	globalA = unsafe.Pointer(&A{
		B: 0,
		C: "12",
		D: pointer.ToString("12.E"),
	})

	var wg sync.WaitGroup
	wg.Add(100)
	for i := 0; i < 100; i++ {
		go worker(i, &wg)
	}
	wg.Wait()
}

func worker(workerID int, wg *sync.WaitGroup) {
	defer wg.Done()

	for i := 0; i < 100; i++ {
		for j := 0; ; j++ {
			original := globalA
			copied := copyA((*A)(original))
			log.WithField("workerID", workerID).WithField("iter", i).WithField("retry", j).WithField("A.B", copied.B).Infof("Copying A")
			copied.B += 1
			if atomic.CompareAndSwapPointer(&globalA, original, unsafe.Pointer(&copied)) {
				log.WithField("workerID", workerID).WithField("iter", i).WithField("retry", j).WithField("A.B", copied.B).Infof("OK")
				break
			} else {
				log.WithField("workerID", workerID).WithField("iter", i).WithField("retry", j).WithField("A.B", copied.B).Infof("Fail, Will retry")
			}
		}
	}
}

func copyA(a *A) A {
	return A{
		B: a.B,
		C: a.C,
		D: pointer.ToString(pointer.GetString(a.D)),
	}
}