Fix deadlock between TRMS resource reclaim and Lnb.close() (8e6b2b88) · Commits · e / os / android_frameworks_base

media/java/android/media/tv/tuner/Lnb.java

+45 −13

Original line number	Original line	Diff line number	Diff line
	@@ -25,6 +25,8 @@ import android.hardware.tv.tuner.LnbPosition;
	import android.hardware.tv.tuner.LnbTone;		import android.hardware.tv.tuner.LnbTone;
	import android.hardware.tv.tuner.LnbVoltage;		import android.hardware.tv.tuner.LnbVoltage;
	import android.media.tv.tuner.Tuner.Result;		import android.media.tv.tuner.Tuner.Result;
			import android.media.tv.tunerresourcemanager.TunerResourceManager;
			import android.util.Log;

	import java.lang.annotation.Retention;		import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;		import java.lang.annotation.RetentionPolicy;
	@@ -147,10 +149,13 @@ public class Lnb implements AutoCloseable {
	public static final int EVENT_TYPE_LNB_OVERLOAD = LnbEventType.LNB_OVERLOAD;		public static final int EVENT_TYPE_LNB_OVERLOAD = LnbEventType.LNB_OVERLOAD;

	private static final String TAG = "Lnb";		private static final String TAG = "Lnb";
			private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);

	Map<LnbCallback, Executor> mCallbackMap =		Map<LnbCallback, Executor> mCallbackMap =
	new HashMap<LnbCallback, Executor>();		new HashMap<LnbCallback, Executor>();
	Tuner mOwner;		Tuner mOwner;
			TunerResourceManager mTunerResourceManager;
			int mClientId;
	private final Object mCallbackLock = new Object();		private final Object mCallbackLock = new Object();


	@@ -174,6 +179,10 @@ public class Lnb implements AutoCloseable {
	}		}
	}		}
	setOwner(tuner);		setOwner(tuner);
			if (mOwner != null) {
			mTunerResourceManager = mOwner.getTunerResourceManager();
			mClientId = mOwner.getClientId();
			}
	}		}

	/**		/**
	@@ -210,6 +219,8 @@ public class Lnb implements AutoCloseable {
	Objects.requireNonNull(newOwner, "newOwner must not be null");		Objects.requireNonNull(newOwner, "newOwner must not be null");
	synchronized (mLock) {		synchronized (mLock) {
	mOwner = newOwner;		mOwner = newOwner;
			mTunerResourceManager = newOwner.getTunerResourceManager();
			mClientId = newOwner.getClientId();
	}		}
	}		}

	@@ -317,6 +328,8 @@ public class Lnb implements AutoCloseable {
	* Releases the LNB instance.		* Releases the LNB instance.
	*/		*/
	public void close() {		public void close() {
			acquireTRMSLock("close()");
			try {
	synchronized (mLock) {		synchronized (mLock) {
	if (mIsClosed) {		if (mIsClosed) {
	return;		return;
	@@ -333,5 +346,24 @@ public class Lnb implements AutoCloseable {
	mCallbackMap.clear();		mCallbackMap.clear();
	}		}
	}		}
			} finally {
			releaseTRMSLock();
			}
			}

			private void acquireTRMSLock(String functionNameForLog) {
			if (DEBUG) {
			Log.d(TAG, "ATTEMPT:acquireLock() in " + functionNameForLog
			+ "for clientId:" + mClientId);
			}
			if (!mTunerResourceManager.acquireLock(mClientId)) {
			Log.e(TAG, "FAILED:acquireLock() in " + functionNameForLog
			+ " for clientId:" + mClientId + " - this can cause deadlock between"
			+ " Tuner API calls and onReclaimResources()");
			}
			}

			private void releaseTRMSLock() {
			mTunerResourceManager.releaseLock(mClientId);
	}		}
	}		}

media/java/android/media/tv/tuner/Tuner.java

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -903,6 +903,9 @@ public class Tuner implements AutoCloseable {
	}		}
	}		}

			/**
			* Releases Lnb resource if held. TRMS lock must be acquired prior to calling this function.
			*/
	private void closeLnb() {		private void closeLnb() {
	mLnbLock.lock();		mLnbLock.lock();
	try {		try {
	@@ -2806,6 +2809,10 @@ public class Tuner implements AutoCloseable {
	return mClientId;		return mClientId;
	}		}

			/* package */ TunerResourceManager getTunerResourceManager() {
			return mTunerResourceManager;
			}

	private void acquireTRMSLock(String functionNameForLog) {		private void acquireTRMSLock(String functionNameForLog) {
	if (DEBUG) {		if (DEBUG) {
	Log.d(TAG, "ATTEMPT:acquireLock() in " + functionNameForLog		Log.d(TAG, "ATTEMPT:acquireLock() in " + functionNameForLog