diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index c24db7f4909c..20111f8da5cb 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3747,7 +3747,7 @@ int perf_event__process_feature(struct perf_session *session,
 		return 0;
 
 	ff.buf  = (void *)fe->data;
-	ff.size = event->header.size - sizeof(event->header);
+	ff.size = event->header.size - sizeof(*fe);
 	ff.ph = &session->header;
 
 	if (feat_ops[feat].process(&ff, NULL))