Security is disabled, why and how to configure the security.context? - php

Question

I'm using Symfony 2.3 and I've created a custom user provider and everything works fine so far except for that following message shows:
Weird thing is that for example in Twig I can do:
{{ app.user.username }}
And it prints fine the username of the logged user.
I've tracked the printing of that message in this view and this is the corresponding controller.
Seems that the class SecurityDataCollector is initialized with a parameter of type SecurityContextInterface with a value of $this->get('security.context', ContainerInterface::NULL_ON_INVALID_REFERENCE)
The problem seems to be that security.context does not exists and I don't know how to set that security context and in the example they don't set them. How can I fix this?
---- app/config/security.yml ----
security:
role_hierarchy:
ROLE_ADMIN: ROLE_USER
ROLE_SUPER_ADMIN: ROLE_ADMIN
encoders:
Company\Shared\CompanyldapBundle\Security\User\ldapUser: plaintext
providers:
ldap_user_provider:
id: ldap_user_provider
firewalls:
main:
provider: ldap_user_provider
pattern: ^/
form_login:
login_path: login
check_path: login_check
logout: true
anonymous: true
access_control:
- { path: ^/login$, role: IS_AUTHENTICATED_ANONYMOUSLY }
- { path: ^/(_(profiler|wdt)|css|images|js)/, role: IS_AUTHENTICATED_ANONYMOUSLY }
- { path: ^/, role: ROLE_USER }