diff --git a/v8/src/execution/futex-emulation.cc b/v8/src/execution/futex-emulation.cc
--- a/v8/src/execution/futex-emulation.cc
+++ b/v8/src/execution/futex-emulation.cc
@@ -216,8 +216,10 @@ void FutexEmulation::NotifyAsyncWaiter(FutexWaitListNode* node) {
 }

 void FutexWaitList::AddNode(FutexWaitListNode* node) {
-  DCHECK_NULL(node->prev_);
-  DCHECK_NULL(node->next_);
+  // Bandaid: enforce in release builds. A reentrant Atomics.wait from a nested
+  // message loop can double-add the per-isolate singleton sync-wait node.
+  CHECK_NULL(node->prev_);
+  CHECK_NULL(node->next_);
   auto [it, inserted] =
       location_lists_.insert({node->wait_location_, HeadAndTail{node, node}});
   if (!inserted) {