diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index fc3b1e0..564377d 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -290,6 +290,7 @@
 sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
 		u64 min_hit, struct callchain_param *param __maybe_unused)
 {
+	*rb_root = RB_ROOT;
 	__sort_chain_flat(rb_root, &root->node, min_hit);
 }