possible deadlock fix

Author: omerfirmak

cmd/migration-checker/main.go

@@ -257,8 +257,10 @@ func loadZkTrie(zkTrie *trie.ZkTrie, top, paranoid bool) chan map[string][]byte
 		}, func(f func()) {
 			<-trieLoaders
 			go func() {
+				defer func() {
+					trieLoaders <- struct{}{}
+				}()
 				f()
-				trieLoaders <- struct{}{}
 			}()
 		}, parallelismCutoffDepth, paranoid)
 		zkDone <- zkLeafMap

trie/zk_trie.go

@@ -272,7 +272,7 @@ func (t *ZkTrie) countLeaves(depth int, root *zkt.Hash, cb func(key, value []byt
 		return 1
 	} else {
 		if depth < parallelismCutoffDepth {
-			count := make(chan uint64)
+			count := make(chan uint64, 1)
 			leftT := t.Copy()
 			rightT := t.Copy()
 			go func() {