[DO NOT MERGE] Throw exception if slot has invalid offset am: 69e347f7ef  -s ours am: 1c732801ab am: 78861ad53e  -s ours am: 13df27e68b am: a3912b6a1b
am: 0766ba70c0

Change-Id: Iccf8ecd9b0a5571efe648416ffda156578aeb095