Attacking on a Charge
After moving, you may make a single melee attack. You get a +2 bonus on the attack roll and take a –2 penalty to your AC until the start of your next turn.
A charging character gets a +2 bonus on combat maneuver attack rolls made to bull rush an opponent.
When you attempt to perform a combat maneuver, make an attack roll and add your CMB in place of your normal attack bonus. Add any bonuses you currently have on attack rolls due to spells, feats, and other effects. These bonuses must be applicable to the weapon or attack used to perform the maneuver. The DC of this maneuver is your target's Combat Maneuver Defense. Combat maneuvers are attack rolls, so you must roll for concealment and take any other penalties that would normally apply to an attack roll
So since a bull rush is an attack roll, do you get both the bonus on attacks from charging AND the bonus to perform an bull rush at the end of a charge for a total of +4 to the attempt?
I would say it's a flat +2, other it would've said 'an additional +2 bonus on combat maneuvers'
Its also kind of redundant to call out bull rush as well, since it would have gotten the +2 bonus anyway since it is an attack roll.