diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index de1a3ec68f..ef2ec661e8 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -978,6 +978,7 @@ void CTxMemPool::UpdateChild(txiter entry, txiter child, bool add)
 
 void CTxMemPool::UpdateParent(txiter entry, txiter parent, bool add)
 {
+    AssertLockHeld(cs);
     setEntries s;
     if (add && mapLinks[entry].parents.insert(parent).second) {
         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
diff --git a/src/txmempool.h b/src/txmempool.h
index 4743e1b63a..fbff1afcca 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -568,7 +568,7 @@ private:
     typedef std::map<txiter, TxLinks, CompareIteratorByHash> txlinksMap;
     txlinksMap mapLinks;
 
-    void UpdateParent(txiter entry, txiter parent, bool add);
+    void UpdateParent(txiter entry, txiter parent, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs);
     void UpdateChild(txiter entry, txiter child, bool add);
 
     std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs);