Magento – Magento CMS Page keep redirect to homepage

app/code/core/Mage/Customer/Helper/Data.php copy this file to

app/code/local/Mage/Customer/Helper/Data.php

change this function as you want line 226.

public function getLogoutUrl()
    {
$currentUrl = Mage::helper('core/url')->getCurrentUrl();
if (strpos($currentUrl,'marketplaceaccount') !== false) {
   return $this->_getUrl('marketplace');
   }else 
   {
        return $this->_getUrl('customer/account/logout');
     }
    }

add in your confix.xml in

<frontend>
            <routers>
                <customer>
                    <args>
                        <modules>
                            <company_modulename before="Mage_Customer">Company_Modulename</company_modulename>
                        </modules>
                    </args>
                </customer>
            </routers>
        </frontend>

these is you controller

require_once 'Mage/Customer/controllers/AccountController.php';
class Company_Modulename_AccountController extends Mage_Customer_AccountController
{
    public function logoutAction()
{
    $this->_getSession()->logout()
        ->renewSession();
      //add your code here
    $this->_redirect('*/*/logoutSuccess');
}
}