diff --git a/xpcom/ds/PLDHashTable.h b/xpcom/ds/PLDHashTable.h
index ba5b92719169..29b85b18f361 100644
--- a/xpcom/ds/PLDHashTable.h
+++ b/xpcom/ds/PLDHashTable.h
@@ -186,8 +186,12 @@ private:
   static const uint32_t kReadMax = 9999;
   static const uint32_t kWrite   = 10000;
 
-  mutable mozilla::Atomic<uint32_t> mState;
-  mutable mozilla::Atomic<uint32_t> mIsWritable;
+  mutable mozilla::Atomic<uint32_t,
+                          mozilla::SequentiallyConsistent,
+                          mozilla::recordreplay::Behavior::DontPreserve> mState;
+  mutable mozilla::Atomic<uint32_t,
+                          mozilla::SequentiallyConsistent,
+                          mozilla::recordreplay::Behavior::DontPreserve> mIsWritable;
 };
 #endif
 
diff --git a/xpcom/string/nsSubstring.cpp b/xpcom/string/nsSubstring.cpp
index 289d911bacc3..a2c107df82b9 100644
--- a/xpcom/string/nsSubstring.cpp
+++ b/xpcom/string/nsSubstring.cpp
@@ -104,12 +104,16 @@ public:
            uintptr_t(getpid()), uintptr_t(pthread_self()));
   }
 
-  Atomic<int32_t> mAllocCount;
-  Atomic<int32_t> mReallocCount;
-  Atomic<int32_t> mFreeCount;
-  Atomic<int32_t> mShareCount;
-  Atomic<int32_t> mAdoptCount;
-  Atomic<int32_t> mAdoptFreeCount;
+  typedef Atomic<int32_t,
+                 mozilla::SequentiallyConsistent,
+                 mozilla::recordreplay::Behavior::DontPreserve> AtomicInt;
+
+  AtomicInt mAllocCount;
+  AtomicInt mReallocCount;
+  AtomicInt mFreeCount;
+  AtomicInt mShareCount;
+  AtomicInt mAdoptCount;
+  AtomicInt mAdoptFreeCount;
 };
 static nsStringStats gStringStats;
 #define STRING_STAT_INCREMENT(_s) (gStringStats.m ## _s ## Count)++