CTA2075: Fix possible race condition

When accessing the MediaCodecs from the audio service callback the
client can still change the codecs which are tracked for receiving
updates. Hence, lock the parameterupdate when iterating over the
loudness controller codecs.

Test: atest "CtsMediaAudioTestCases:android.media.audio.cts.LoudnessCodecControllerTest#multipleLcc_withRegisteredCodecs_triggerUpdate" --iterations 100
Bug: 321868864
Change-Id: I7aedc85d9d143497d089ae7f613f9fb5897f916d

2 files changed, 11 insertions, 9 deletions

diff --git a/media/java/android/media/LoudnessCodecController.java b/media/java/android/media/LoudnessCodecController.java
index b3e5c52b27b3..836b228cb6f9 100644
--- a/media/java/android/media/LoudnessCodecController.java
+++ b/media/java/android/media/LoudnessCodecController.java
@@ -32,12 +32,13 @@ import androidx.annotation.Nullable;
 
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
 
 /**
  * Class for getting recommended loudness parameter updates for audio decoders as they are used
@@ -339,9 +340,12 @@ public class LoudnessCodecController implements SafeCloseable {
     }
 
     /** @hide */
-    /*package*/ Map<LoudnessCodecInfo, Set<MediaCodec>> getRegisteredMediaCodecs() {
+    /*package*/ void mediaCodecsConsume(
+            Consumer<Entry<LoudnessCodecInfo, Set<MediaCodec>>> consumer) {
         synchronized (mControllerLock) {
-            return mMediaCodecs;
+            for (Entry<LoudnessCodecInfo, Set<MediaCodec>> entry : mMediaCodecs.entrySet()) {
+                consumer.accept(entry);
+            }
         }
     }
 
diff --git a/media/java/android/media/LoudnessCodecDispatcher.java b/media/java/android/media/LoudnessCodecDispatcher.java
index 46be54be55ec..fa08658a214f 100644
--- a/media/java/android/media/LoudnessCodecDispatcher.java
+++ b/media/java/android/media/LoudnessCodecDispatcher.java
@@ -32,7 +32,6 @@ import androidx.annotation.NonNull;
 
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.Set;
@@ -81,16 +80,15 @@ public class LoudnessCodecDispatcher implements CallbackUtil.DispatcherStub {
                     mConfiguratorListener.computeIfPresent(listener, (l, lcConfig) -> {
                         // send the appropriate bundle for the user to update
                         if (lcConfig.getSessionId() == sessionId) {
-                            final Map<LoudnessCodecInfo, Set<MediaCodec>> mediaCodecsMap =
-                                    lcConfig.getRegisteredMediaCodecs();
-                            for (LoudnessCodecInfo codecInfo : mediaCodecsMap.keySet()) {
+                            lcConfig.mediaCodecsConsume(mcEntry -> {
+                                final LoudnessCodecInfo codecInfo = mcEntry.getKey();
                                 final String infoKey = Integer.toString(codecInfo.hashCode());
                                 Bundle bundle = null;
                                 if (params.containsKey(infoKey)) {
                                     bundle = new Bundle(params.getPersistableBundle(infoKey));
                                 }
 
-                                final Set<MediaCodec> mediaCodecs = mediaCodecsMap.get(codecInfo);
+                                final Set<MediaCodec> mediaCodecs = mcEntry.getValue();
                                 for (MediaCodec mediaCodec : mediaCodecs) {
                                     final String mediaCodecKey = Integer.toString(
                                             mediaCodec.hashCode());
@@ -121,7 +119,7 @@ public class LoudnessCodecDispatcher implements CallbackUtil.DispatcherStub {
                                         break;
                                     }
                                 }
-                            }
+                            });
                         }
                         return lcConfig;
                     });