  Linearizability is the de facto consistency condition for concurrent objects,
widely used in theory and practice. Loosely speaking, linearizability
classifies concurrent executions as correct if operations on shared objects
appear to take effect instantaneously during the operation execution time. This
paper calls attention to a somewhat-neglected aspect of linearizability:
restrictions on how pending invocations are handled, an issue that has become
increasingly important for software running on systems with non-volatile main
memory. Interestingly, the original published definition of linearizability
includes a typo (a symbol is missing a prime) that concerns exactly this issue.
In this paper we point out the typo and provide an amendment to make the
definition complete. We believe that pointing this typo out rigorously and
proposing a fix is important and timely.
