--- a/dom/indexedDB/ActorsParent.cpp
+++ b/dom/indexedDB/ActorsParent.cpp
@@ -3939,16 +3939,19 @@ UpgradeIndexDataValuesFunction::OnFuncti
   rv = ReadOldCompressedIDVFromBlob(oldBlob, oldBlobLength, oldIdv);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   UniqueFreePtr<uint8_t> newIdv;
   uint32_t newIdvLength;
   rv = MakeCompressedIndexDataValues(oldIdv, newIdv, &newIdvLength);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
 
   std::pair<uint8_t*, int> data(newIdv.release(), newIdvLength);
 
   nsCOMPtr<nsIVariant> result = new storage::AdoptedBlobVariant(data);
 
   result.forget(aResult);
   return NS_OK;
 }