[$] Randomness for kmalloc()

The kernel's address-space layout randomization is intended to make lifeharder for attackers by changing the placement of kernel text and data ateach boot. With this randomization, an attacker cannot know ahead of timewhere a vulnerable target will be found on any given system. There aretechniques, though, that can be effective without knowing precisely where agiven object is stored. As a way of hardening systems against suchattacks, the kernel will be gaining yet another form of randomization.