diff --git a/services/audioflinger/TrackMetrics.h b/services/audioflinger/TrackMetrics.h
index 6fc70d6..ed3928a 100644
--- a/services/audioflinger/TrackMetrics.h
+++ b/services/audioflinger/TrackMetrics.h
@@ -113,7 +113,8 @@
         mDeviceStartupMs.add(startupMs);
     }
 
-    void updateMinMaxVolume(int64_t durationNs, double deviceVolume) {
+    void updateMinMaxVolume_l(int64_t durationNs, double deviceVolume)
+            REQUIRES(mLock) {
         if (deviceVolume > mMaxVolume) {
             mMaxVolume = deviceVolume;
             mMaxVolumeDurationNs = durationNs;
@@ -165,7 +166,7 @@
             mDeviceTimeNs += durationNs;
             mCumulativeTimeNs += durationNs;
         }
-        updateMinMaxVolume(durationNs, mVolume); // always update.
+        updateMinMaxVolume_l(durationNs, mVolume); // always update.
         mVolume = volume;
         mLastVolumeChangeTimeNs = timeNs;
     }