diff --git a/runtime/base/mutex.cc b/runtime/base/mutex.cc
index 05e3a83..ff72d16 100644
--- a/runtime/base/mutex.cc
+++ b/runtime/base/mutex.cc
@@ -47,7 +47,7 @@
 
 struct AllMutexData {
   // A guard for all_mutexes_ that's not a mutex (Mutexes must CAS to acquire and busy wait).
-  AtomicInteger all_mutexes_guard;
+  Atomic<const BaseMutex*> all_mutexes_guard;
   // All created mutexes guarded by all_mutexes_guard_.
   std::set<BaseMutex*>* all_mutexes;
   AllMutexData() : all_mutexes(NULL) {}
@@ -57,12 +57,12 @@
 class ScopedAllMutexesLock {
  public:
   explicit ScopedAllMutexesLock(const BaseMutex* mutex) : mutex_(mutex) {
-    while (!gAllMutexData->all_mutexes_guard.CompareAndSwap(0, reinterpret_cast<int32_t>(mutex))) {
+    while (!gAllMutexData->all_mutexes_guard.CompareAndSwap(0, mutex)) {
       NanoSleep(100);
     }
   }
   ~ScopedAllMutexesLock() {
-    while (!gAllMutexData->all_mutexes_guard.CompareAndSwap(reinterpret_cast<int32_t>(mutex_), 0)) {
+    while (!gAllMutexData->all_mutexes_guard.CompareAndSwap(mutex_, 0)) {
       NanoSleep(100);
     }
   }