how to login to subdomain using symfony security if already loggedin on main domain in other app?

I am already loggedin to main domain. Say example.com (app developed in legacy kohana). I am trying to login to subdmain, say foo.bar.example.com .

foo.example.com is symfony app. Below is my configuration. Dev too bar displays "anonymous" user. It doesn't loggin user from session id in cookie.

security.yml

# To get started with security, check out the documentation:
# http://symfony.com/doc/current/book/security.html
security:

    # http://symfony.com/doc/current/book/security.html#where-do-users-come-from-user-providers
    providers:
        in_memory:
            memory: ~

    firewalls:
        # disables authentication for assets and the profiler, adapt it according to your needs
        dev:
            pattern: ^/(_(profiler|wdt)|css|images|js)/
            security: false

        main:
            anonymous: ~
            # activate different ways to authenticate

            # http_basic: ~
            # http://symfony.com/doc/current/book/security.html#a-configuring-how-your-users-will-authenticate

            # form_login: ~
            # http://symfony.com/doc/current/cookbook/security/form_login_setup.html

Config.yml

framework:
    #esi:             ~
    #translator:      { fallbacks: ["%locale%"] }
    secret:          "%secret%"
    router:
        resource: "%kernel.root_dir%/config/routing.yml"
        strict_requirements: ~
    form:            ~
    csrf_protection: ~
    validation:      { enable_annotations: true }
    #serializer:      { enable_annotations: true }
    default_locale:  "%locale%"
    trusted_hosts:   ~
    trusted_proxies:  %trusted_proxies%
    session:
        # handler_id set to null will use default session handler from php.ini
        handler_id:  'snc_redis.session.handler'
        name: 'MY_COOKIE_NAME'
        cookie_domain: '.example.com'
    fragments:       ~
    http_method_override: true
    request:
        formats:
            pdf: 'application/pdf'
            epub: 'application/epub+zip'


snc_redis:
    session:
        client: session
        prefix: ''
    clients:
        default:
            type: predis
            alias: default
            dsn: %redis_dsn%
            logging: false
            options:
#                profile: 2.6
                profile: 2.2
                connection_persistent: false
        slave:
            type: predis
            alias: slave
            logging: false
            dsn: %redis_dsn_slave%

        session:
            type: predis
            alias: session
            dsn: %redis_dsn%

Do I need to have atleast one authentication provider configured ? or I need to write custom authentication provider something which works like remember me ?

Symfony\Component\Security\Http\Firewall\AbstractAuthenticationListener->handle

has

  if ($this->options['require_previous_session'] && !$request->hasPreviousSession()) {
                throw new SessionUnavailableException('Your session has timed out, or you have disabled cookies.');
            }

and Request has

public function hasPreviousSession()
{
    // the check for $this->session avoids malicious users trying to fake a session cookie with proper name
    return $this->hasSession() && $this->cookies->has($this->session->getName());
}

from how to login to subdomain using symfony security if already loggedin on main domain in other app?