diff --git a/xpcom/ds/nsRefPtrHashtable.h b/xpcom/ds/nsRefPtrHashtable.h
index bf81b013d2b9..27e8248a560f 100644
--- a/xpcom/ds/nsRefPtrHashtable.h
+++ b/xpcom/ds/nsRefPtrHashtable.h
@@ -157,7 +157,7 @@ nsRefPtrHashtable<KeyClass, PtrType>::Put(KeyType aKey,
                                           already_AddRefed<PtrType> aData,
                                           const mozilla::fallible_t&)
 {
-  typename base_type::EntryType* ent = this->PutEntry(aKey);
+  typename base_type::EntryType* ent = this->PutEntry(aKey, mozilla::fallible);
 
   if (!ent) {
     return false;