  Happens-before based data race prediction methods infer from a trace of
events a partial order to check if one event happens before another event. If
two two write events are unordered, they are in a race. We observe that common
tracing methods provide no guarantee that the trace order corresponds to an
actual program run. The consequence of inaccurate tracing is that results
(races) reported are inaccurate. We introduce diagnostic methods to examine if
(1) a race is guaranteed to be correct regardless of any potential
inaccuracies, (2) maybe is incorrect due to inaccurate tracing. We have fully
implemented the approach and provide for an empirical comparison with state of
the art happens-before based race predictors such as FastTrack and SHB.
