Dwayne "The Rock" Johnson, best known for his high-octane action roles, stepped out of his Hollywood comfort zone to take on a bruising dramatic turn in "The Smashing Machine," which premiered at the Venice Film Festival. The former wrestling star and box-office powerhouse plays the real-life, mixed martial arts pioneer Mark Kerr, whose towering physique and prowess in the ring belied a soft-spoken nature and private struggles. The role marks a sharp turn for Johnson, who spent the past two