1 files changed, 17 insertions, 7 deletions
diff --git a/libstdc++-v3/src/mutex.cc b/libstdc++-v3/src/mutex.cc
index a9467c2..e0a9489 100644
--- a/libstdc++-v3/src/mutex.cc
+++ b/libstdc++-v3/src/mutex.cc
@@ -25,6 +25,18 @@
 #include <mutex>
 
 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
+#ifndef _GLIBCXX_HAVE_TLS
+namespace
+{
+  std::mutex&
+  get_once_mutex()
+  {
+    static std::mutex once_mutex;
+    return once_mutex;
+  }
+}
+#endif
+
 namespace std
 {
   const defer_lock_t defer_lock = defer_lock_t();
@@ -43,13 +55,11 @@ namespace std
   template class function<void()>;
   function<void()> __once_functor;
 
-  unique_lock<mutex>* __once_functor_lock;
-
-  mutex&
-  __get_once_mutex()
+  unique_lock<mutex>&
+  __get_once_functor_lock()
   {
-    static mutex once_mutex;
-    return once_mutex;
+    static unique_lock<mutex> once_functor_lock(get_once_mutex(), defer_lock);
+    return once_functor_lock;
   }
 #endif
 
@@ -59,7 +69,7 @@ namespace std
     {
 #ifndef _GLIBCXX_HAVE_TLS
       function<void()> __once_call = std::move(__once_functor);
-      __once_functor_lock->unlock();
+      __get_once_functor_lock().unlock();
 #endif
       __once_call();
     }