diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 935608971899..a0c15f67eabe 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -91,7 +91,7 @@
 #define __rel_string_len(item, src, len) __rel_dynamic_array(char, item, -1)
 
 #undef __assign_rel_str
-#define __assign_rel_str(dst, src)					\
+#define __assign_rel_str(dst)						\
 	do {								\
 		char *__str__ = __get_rel_str(dst);			\
 		int __len__ = __get_rel_dynamic_array_len(dst) - 1;	\
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 2dfaf7fc7bfa..500981eca74d 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -574,7 +574,7 @@ TRACE_EVENT(foo_rel_loc,
 	),
 
 	TP_fast_assign(
-		__assign_rel_str(foo, foo);
+		__assign_rel_str(foo);
 		__entry->bar = bar;
 		__assign_rel_bitmask(bitmask, mask,
 			BITS_PER_BYTE * sizeof(unsigned long));