diff --git a/camera/libcameraservice/CameraService.h b/camera/libcameraservice/CameraService.h
index 41c5d99..3e3e54f 100644
--- a/camera/libcameraservice/CameraService.h
+++ b/camera/libcameraservice/CameraService.h
@@ -181,7 +181,6 @@
         mutable     Condition                   mReady;
                     sp<CameraService>           mCameraService;
                     sp<ISurface>                mSurface;
-                    sp<MemoryHeapBase>          mPreviewBuffer;
                     int                         mPreviewCallbackFlag;
 
                     sp<MediaPlayer>             mMediaPlayerClick;
@@ -197,6 +196,9 @@
                     sp<OverlayRef>              mOverlayRef;
                     int                         mOverlayW;
                     int                         mOverlayH;
+
+        mutable     Mutex                       mPreviewLock;
+                    sp<MemoryHeapBase>          mPreviewBuffer;
     };
 
 // ----------------------------------------------------------------------------