diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 21a78d3..2e418b9 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -132,7 +132,7 @@
 	return 0;
 }
 
-static int process_sample_event(event_t *event)
+static int process_sample_event(event_t *event, struct perf_session *session __used)
 {
 	struct addr_location al;