diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 65c6c73d28fe4094fac7a0df5a9773c7f3cab939..d0c1267741eecb70b7d94239b93db69e0815ccd1 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -653,6 +653,7 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
 	attr.precise_ip	    = precise_ip;
 	attr.mmap_data	    = mmap_data;
 	attr.sample_id_all  = sample_id_all;
+	attr.size	    = sizeof(attr);
 
 	perf_evsel__init(&pevsel->evsel, &attr, idx);
 	return 0;