Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull CPU hotplug fix from Thomas Gleixner:
 "A single fix preventing the concurrent execution of the CPU hotplug
  callback install/invocation machinery. Long standing bug caused by a
  massive brain slip of that Gleixner dude, which went unnoticed for
  almost a year"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Serialize callback invocations proper