diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index f329929535..22ac69295f 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -5414,8 +5414,10 @@ Heap::IncrementalMarkingLimit Heap::IncrementalMarkingLimitReached() {
           max_marking_limit_reached_ =
               std::max<double>(max_marking_limit_reached_, current_percent);
         }
-      } else if (current_percent >= stress_marking_percentage_) {
-        stress_marking_percentage_ = NextStressMarkingLimit();
+      } else if (current_percent >=
+                 stress_marking_percentage_.load(std::memory_order_relaxed)) {
+        stress_marking_percentage_.store(NextStressMarkingLimit(),
+                                         std::memory_order_relaxed);
         return IncrementalMarkingLimit::kHardLimit;
       }
     }
diff --git a/src/heap/heap.h b/src/heap/heap.h
index cd1e4fa4a3..ceb6e9d05c 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -2290,10 +2290,10 @@ class Heap {
 
   // Starts marking when stress_marking_percentage_% of the marking start limit
   // is reached.
-  int stress_marking_percentage_ = 0;
+  std::atomic<int> stress_marking_percentage_{0};
 
-  // Observer that causes more frequent checks for reached incremental marking
-  // limit.
+  // Observer that causes more frequent checks for reached incremental
+  // marking limit.
   AllocationObserver* stress_marking_observer_ = nullptr;
 
   // Observer that can cause early scavenge start.