debug all flow for adding product to cart. In process I found that collectTotal function of quote is not setting price and continuously loops to bug which make redirect to home page.
Validation for configurable product is failed in this file /store/app/code/core/Mage/SalesRule/Model/Rule/Condition/Product/Subselect.php
This file on line number 117 having this function call on configurable product Item validation if (parent::validate($item)) {
which is somehow because this validate($item) function is not in it parent class. Instead this validate($item) is in Class Mage_Rule_Model_Condition_Combine so modified it to if (Mage_Rule_Model_Condition_Combine::validate($item)) {.