diff --git a/p2p/enode/iter.go b/p2p/enode/iter.go
index 54c2fc7258..d0ccf984d3 100644
--- a/p2p/enode/iter.go
+++ b/p2p/enode/iter.go
@@ -356,6 +356,7 @@ func (m *FairMix) AddSource(it Iterator) {
 	defer m.mu.Unlock()
 
 	if m.closed == nil {
+		it.Close()
 		return
 	}
 	m.wg.Add(1)