diff --git a/core/chain_indexer.go b/core/chain_indexer.go
index c0c2c4f7f9..cf9412c4b4 100644
--- a/core/chain_indexer.go
+++ b/core/chain_indexer.go
@@ -439,6 +439,9 @@ func (c *ChainIndexer) Sections() (uint64, uint64, common.Hash) {
 
 // AddChildIndexer adds a child ChainIndexer that can use the output of this one
 func (c *ChainIndexer) AddChildIndexer(indexer *ChainIndexer) {
+	if c == indexer {
+		return
+	}
 	c.lock.Lock()
 	defer c.lock.Unlock()