ActiveModel::MassAssignmentSecurity::Error: Can't mass-assign protected attributes even with whitelist_attributes=false

ActiveModel::MassAssignmentSecurity::Error: Can't mass-assign protected
attributes even with whitelist_attributes=false

I'm migrating from rails 2.3 to 3.2 and want to use strong_parameters. I
changed config.active_record.whitelist_attributes config true to false,
but that didn't helped.