core: add check in AddChildIndexer to avoid double lock (ethereum#20982)

This fixes a theoretical double lock condition which could occur in indexer.AddChildIndexer(indexer) Nobody would ever do that though. Co-authored-by: Felix Lange <[email protected]>
0xdapper · Apr 27, 2020 · ba068d4 · ba068d4
1 parent e32ee6a
commit ba068d4
Showing 1 changed file with 3 additions and 0 deletions.
diff --git 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 indexer == c {
+		panic("can't add indexer as a child of itself")
+	}
 	c.lock.Lock()
 	defer c.lock.Unlock()