diff --git a/dom/storage/DOMStorageDBThread.h b/dom/storage/DOMStorageDBThread.h
index a2f6889f9119..0ffbf6df068f 100644
--- a/dom/storage/DOMStorageDBThread.h
+++ b/dom/storage/DOMStorageDBThread.h
@@ -10,6 +10,7 @@
 #include "prthread.h"
 #include "prinrval.h"
 #include "nsTArray.h"
+#include "mozilla/Atomics.h"
 #include "mozilla/Monitor.h"
 #include "mozilla/storage/StatementCache.h"
 #include "nsString.h"
@@ -292,7 +293,7 @@ private:
 
   // Whether DB has already been open, avoid races between main thread reads
   // and pending DB init in the background I/O thread
-  bool mDBReady;
+  Atomic<bool, ReleaseAcquire> mDBReady;
 
   // State of the database initiation
   nsresult mStatus;