Win 7 64bit, GTX 770 oc
Broken: 2.79 ac28a4f
When trying to move/rotate an empty target/control for a Copy Rotation/Copy Location, while Armature>>Ghost is enabled, Blender will crash.
In my rig (metarig), I have IK constraints (length 1) set to other bones; if those are removed, Blender won't crash; if even one is set, Blender crashes.
Increase the Range in the Armature's Ghost from 0, then try to rotate the arrow above the head.
Or if you rotate the arrow first, enable ghost, then select the arrow again, it crashes.
note: adding an IK constraint to the bone (targeting the empty) stops the crash. The crash also stops with 0 influence/chain/etc but only if the target is set to the specific empty (in the Copy Rotation constraint)