为什么这个while会陷入死循环呢？

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public void Mirror(TreeNode root) {
        while(root.left!=null||root.right!=null){
        	TreeNode rootLeft = root.left;
            TreeNode rootRight = root.right;
            root.left = rootRight;
            root.right = rootLeft;
            while(root.left!=null){
            	System.out.println(root.left.val);
                Mirror(root.left);
            }
            while(root.right!=null){
            	System.out.println(root.right.val);
                Mirror(root.right);
            }
        }
    }
}