Why does this script put Unity into a not responding state?

I can't figure out why this script is constantly crashing Unity and I'm tired of trying to figure it out, I'd like some help.

using UnityEngine; using System.Collections;

 public class TerrainGenerator : MonoBehaviour
 {
     public GameObject voxel;
     public float voxelSize;
     public float chunkHeight;
     public int chunkSize;
     
     float x;
     float y;
     void Awake ()
     {
         Mesh mesh = new Mesh ();
         Vector3 [] vertices = new Vector3 [4]
         {
             new Vector3 (0, 0, 0), new Vector3 (voxelSize, 0, 0), new Vector3 (voxelSize, 0, voxelSize), new Vector3 (0, 0, voxelSize)
         };
         int [] triangles = new int [6]
         {
             1, 3, 0, 1, 3, 2
         };
         mesh.vertices = vertices;
         mesh.triangles = triangles;
         for (float i = 0; i < chunkSize; i += voxelSize)
         {
             x = 0;
             y += 0.1f * voxelSize;
             for (float f = 0; f <= chunkSize; f += voxelSize)
             {
                 x += 0.1f * voxelSize;
                 Vector3 position = new Vector3 (f, Mathf.Round (Mathf.PerlinNoise (x, y) * chunkHeight) * voxelSize, i);
                 GameObject voxelTransform = (GameObject) Instantiate (voxel, position, Quaternion.identity);
                 MeshFilter mf = voxelTransform.GetComponent <MeshFilter> ();
                 mf.mesh = mesh;
             }
         }
     }
 }