diff --git a/media/libmedia/mediametadataretriever.cpp b/media/libmedia/mediametadataretriever.cpp
index 40fd022..9196f9f 100644
--- a/media/libmedia/mediametadataretriever.cpp
+++ b/media/libmedia/mediametadataretriever.cpp
@@ -35,6 +35,8 @@
 sp<IMediaPlayerService> MediaMetadataRetriever::sService;
 sp<MediaMetadataRetriever::DeathNotifier> MediaMetadataRetriever::sDeathNotifier;
 
+Mutex MediaMetadataRetriever::sLock;
+
 const sp<IMediaPlayerService> MediaMetadataRetriever::getService()
 {
     Mutex::Autolock lock(sServiceLock);
@@ -143,6 +145,7 @@
     ALOGV("getFrameAtTime: time(%" PRId64 " us) option(%d) colorFormat(%d) metaOnly(%d)",
             timeUs, option, colorFormat, metaOnly);
     Mutex::Autolock _l(mLock);
+    Mutex::Autolock _gLock(sLock);
     if (mRetriever == 0) {
         ALOGE("retriever is not initialized");
         return NULL;
@@ -155,6 +158,7 @@
     ALOGV("getImageAtIndex: index(%d) colorFormat(%d) metaOnly(%d) thumbnail(%d)",
             index, colorFormat, metaOnly, thumbnail);
     Mutex::Autolock _l(mLock);
+    Mutex::Autolock _gLock(sLock);
     if (mRetriever == 0) {
         ALOGE("retriever is not initialized");
         return NULL;
@@ -167,6 +171,7 @@
     ALOGV("getImageRectAtIndex: index(%d) colorFormat(%d) rect {%d, %d, %d, %d}",
             index, colorFormat, left, top, right, bottom);
     Mutex::Autolock _l(mLock);
+    Mutex::Autolock _gLock(sLock);
     if (mRetriever == 0) {
         ALOGE("retriever is not initialized");
         return NULL;
@@ -180,6 +185,7 @@
     ALOGV("getFrameAtIndex: index(%d), colorFormat(%d) metaOnly(%d)",
             index, colorFormat, metaOnly);
     Mutex::Autolock _l(mLock);
+    Mutex::Autolock _gLock(sLock);
     if (mRetriever == 0) {
         ALOGE("retriever is not initialized");
         return NULL;