azure data disk list is corrupted after attach/detach disk

[andyzhangx]

What happened:
In Azure disk attach/detach function, it uses slice(disks) to store the disk list:

kubernetes/staging/src/k8s.io/legacy-cloud-providers/azure/azure_controller_standard.go

Line 44 in f01c140

disks := *vm.StorageProfile.DataDisks

And after disks changed, the original vm.StorageProfile.DataDisks would also be changed, so original azure data disk list is corrupted after attach/detach disk

example code as below:

func main() {
    var disks *[]string 
    disks = &[]string{"disk1", "disk2", "disk3", "disk4"}
    copy := *disks

    //detach a disk
    copy = append(copy[:1], copy[2:]...)

    
    fmt.Println("disks = ", *disks)
    fmt.Println("copy = ", copy)
}


# ./test
disks =  [disk1 disk3 disk4 disk4]
copy =  [disk1 disk3 disk4]

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version):
• Cloud provider or hardware configuration:
• OS (e.g: cat /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Network plugin and version (if this is a network-related bug):
• Others:

/sig azure
/assign