Support expired timer information in AnrTimer (d8ee8184) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/TimeoutRecord.java

+8 −0

Original line number	Diff line number	Diff line
		@@ -220,6 +220,14 @@ public class TimeoutRecord {
		return this;
		}

		/**
		* Return the expired timer.
		*/
		@Nullable
		public AutoCloseable getExpiredTimer() {
		return mExpiredTimer;
		}

		/** Close the ExpiredTimer, if one is present. getExpiredTimer will return null after this. */
		public void closeExpiredTimer() {
		try {

services/core/java/com/android/server/utils/AnrTimer.java

+64 −22

Original line number	Diff line number	Diff line
		@@ -301,10 +301,10 @@ public class AnrTimer<V> implements AutoCloseable {
		/**
		* A target process may be modified when its timer expires. The modification (if any) will be
		* undone if the expiration is discarded, but is persisted if the expiration is accepted. If
		* the expiration is accepted, then a TimerLock is returned to the client. The client must
		* close the TimerLock to complete the state machine.
		* the expiration is accepted, then a ExpiredTimer is returned to the client. The client must
		* close the ExpiredTimer to complete the state machine.
		*/
		private class TimerLock implements AutoCloseable {
		public static class ExpiredTimer implements AutoCloseable {
		// Detect failures to close.
		private final CloseGuard mGuard = new CloseGuard();

		@@ -314,7 +314,11 @@ public class AnrTimer<V> implements AutoCloseable {
		// Allow multiple calls to close().
		private boolean mClosed = false;

		TimerLock() {
		// The timer ID.
		final int mTimerId;

		ExpiredTimer(int id) {
		mTimerId = id;
		mGuard.open("AnrTimer.release");
		}

		@@ -401,10 +405,14 @@ public class AnrTimer<V> implements AutoCloseable {
		@GuardedBy("mLock")
		private final ArrayMap<V, Integer> mTimerIdMap = new ArrayMap<>();

		/** Reverse map from timer ID to client argument. */
		/** Reverse map from timer ID to client argument, needed by the expire() callback. */
		@GuardedBy("mLock")
		private final SparseArray<V> mTimerArgMap = new SparseArray<>();

		/** Map from timer ID to ExpiredTimer. */
		@GuardedBy("mLock")
		private final SparseArray<ExpiredTimer> mExpiredTimers = new SparseArray<>();

		/** The highwater mark of started, but not closed, timers. */
		@GuardedBy("mLock")
		private int mMaxStarted = 0;
		@@ -528,7 +536,7 @@ public class AnrTimer<V> implements AutoCloseable {
		abstract boolean cancel(@NonNull V arg);

		@Nullable
		abstract TimerLock accept(@NonNull V arg);
		abstract ExpiredTimer accept(@NonNull V arg);

		abstract boolean discard(@NonNull V arg);

		@@ -564,7 +572,7 @@ public class AnrTimer<V> implements AutoCloseable {
		/** accept() is a no-op when the feature is disabled. */
		@Override
		@Nullable
		TimerLock accept(@NonNull V arg) {
		ExpiredTimer accept(@NonNull V arg) {
		return null;
		}

		@@ -684,28 +692,31 @@ public class AnrTimer<V> implements AutoCloseable {

		/**
		* Accept a timer in the framework-level handler. The timeout has been accepted and the
		* client's timeout handler is executing. If the function returns a non-null TimerLock then
		* the associated process may have been paused (or otherwise modified in preparation for
		* debugging). The TimerLock must be closed to allow the process to continue, or to be
		* dumped in an AnrReport.
		* client's timeout handler is executing. If the function returns a non-null ExpiredTimer
		* then the associated process may have been paused (or otherwise modified in preparation
		* for debugging). The ExpiredTimer must be closed.
		*/
		@Override
		@Nullable
		TimerLock accept(@NonNull V arg) {
		ExpiredTimer accept(@NonNull V arg) {
		synchronized (mLock) {
		Integer timer = removeLocked(arg);
		ExpiredTimer timer = removeLockedTimer(arg);
		if (timer == null) {
		notFoundLocked("accept", arg);
		return null;
		}
		// Race conditions may lead to timer acceptance after the service was closed.
		if (mNative == 0) return null;
		boolean accepted = nativeAnrTimerAccept(mNative, timer);
		boolean accepted = nativeAnrTimerAccept(mNative, timer.mTimerId);
		trace("accept", timer);
		// If "accepted" is true then the native layer has pending operations against this
		// timer. Wrap the timer ID in a TimerLock and return it to the caller. If
		// timer. Wrap the timer ID in a ExpiredTimer and return it to the caller. If
		// "accepted" is false then the native later does not have any pending operations.
		return accepted ? new TimerLock() : null;
		if (!accepted) {
		timer.close();
		timer = null;
		}
		return timer;
		}
		}

		@@ -770,15 +781,32 @@ public class AnrTimer<V> implements AutoCloseable {
		}
		}

		/**
		* Delete the entries associated with arg from the maps and return the ExpiredTimer of the
		* timer, if any.
		*/
		@GuardedBy("mLock")
		private ExpiredTimer removeLockedTimer(V arg) {
		final Integer r = mTimerIdMap.remove(arg);
		ExpiredTimer l = null;
		if (r != null) {
		mTimerArgMap.remove(r);
		l = mExpiredTimers.removeReturnOld(r);
		}
		return l;
		}

		/**
		* Delete the entries associated with arg from the maps and return the ID of the timer, if
		* any.
		* any. If there is a ExpiredTimer present, it is closed.
		*/
		@GuardedBy("mLock")
		private Integer removeLocked(V arg) {
		Integer r = mTimerIdMap.remove(arg);
		final Integer r = mTimerIdMap.remove(arg);
		if (r != null) {
		mTimerArgMap.remove(r);
		ExpiredTimer l = mExpiredTimers.removeReturnOld(r);
		if (l != null) l.close();
		}
		return r;
		}
		@@ -843,9 +871,9 @@ public class AnrTimer<V> implements AutoCloseable {
		/**
		* Accept the expired timer associated with arg. This indicates that the caller considers the
		* timer expiration to be a true ANR. (See {@link #discard} for an alternate response.) The
		* function stores a {@link TimerLock} in the {@link TimeoutRecord} argument. The TimerLock
		* records information about the expired timer for retrieval during ANR report generation.
		* After this call, the timer does not exist.
		* function stores a {@link ExpiredTimer} in the {@link TimeoutRecord} argument. The
		* ExpiredTimer records information about the expired timer for retrieval during ANR report
		* generation. After this call, the timer does not exist.
		*
		* It is a protocol error to accept a running timer, however, the running timer will be
		* canceled.
		@@ -887,7 +915,7 @@ public class AnrTimer<V> implements AutoCloseable {
		@Keep
		private boolean expire(int timerId, int pid, int uid, long elapsedMs) {
		trace("expired", timerId, pid, uid, mLabel, elapsedMs);
		V arg = null;
		final V arg;
		synchronized (mLock) {
		arg = mTimerArgMap.get(timerId);
		if (arg == null) {
		@@ -896,6 +924,7 @@ public class AnrTimer<V> implements AutoCloseable {
		mTotalErrors++;
		return false;
		}
		mExpiredTimers.put(timerId, new ExpiredTimer(timerId));
		mTotalExpired++;
		}
		final Message msg = Message.obtain(mHandler, mWhat, arg);
		@@ -965,6 +994,19 @@ public class AnrTimer<V> implements AutoCloseable {
		mFeature.setTime(now);
		}

		/**
		* Return the ExpiredTimer associated with a TimeoutRecord. The TimeoutRecord is not modified.
		*/
		@Nullable
		public static ExpiredTimer expiredTimer(TimeoutRecord tr) {
		AutoCloseable expiredTimer = tr.getExpiredTimer();
		if (expiredTimer instanceof ExpiredTimer lock) {
		return lock;
		} else {
		return null;
		}
		}

		/**
		* Ensure any native resources are freed when the object is GC'ed. Best practice is to close
		* the object explicitly, but overriding finalize() avoids accidental leaks.

services/tests/servicestests/src/com/android/server/utils/AnrTimerTest.java

+44 −1

Original line number	Diff line number	Diff line
		@@ -31,6 +31,7 @@ import android.util.Log;
		import androidx.test.filters.SmallTest;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.os.TimeoutRecord;

		import org.junit.Ignore;
		import org.junit.Test;
		@@ -52,7 +53,7 @@ public class AnrTimerTest {
		private static final int MSG_TIMEOUT = 1;

		// The test argument includes a pid and uid, and a tag. The tag is used to distinguish
		// different message instances. Additional fields (like what) capture delivery information
		// different message instances. Additional fields (like "what") capture delivery information
		// that is checked by the test.
		private static class TestArg {
		final int pid;
		@@ -531,6 +532,48 @@ public class AnrTimerTest {
		}
		}

		/**
		* Test the ExpiredTimer feature.
		*/
		@Test
		public void testExpiredTimer() throws Exception {
		assumeTrue(AnrTimer.nativeTimersSupported());
		AnrTimer.Args args =
		new AnrTimer.Args()
		.enable(true)
		.testMode(true);

		Helper helper = new Helper(1);
		TestArg t1 = new TestArg(1, 1);
		TestArg t2 = new TestArg(2, 2);
		try (TestAnrTimer timer = new TestAnrTimer(helper, args)) {
		Stepper stepper = new Stepper(timer, helper);

		timer.start(t1, 100);
		stepper.stepAndWait(100);
		timer.start(t2, 100);
		stepper.stepAndWait(200);
		TestResult[] result = helper.results(2);

		assertThat(timer.discard(t1)).isTrue();
		assertThat(timer.discard(t1)).isFalse();
		TimeoutRecord tr1a = TimeoutRecord.forApp("testing purposes");
		timer.accept(t1, tr1a);
		assertThat(tr1a.getExpiredTimer()).isNull();

		TimeoutRecord tr2a = TimeoutRecord.forApp("testing purposes");
		timer.accept(t2, tr2a);
		assertThat(tr2a.getExpiredTimer()).isNotNull();
		assertThat(tr2a.getExpiredTimer()).isNotNull();
		tr2a.closeExpiredTimer();
		assertThat(tr2a.getExpiredTimer()).isNull();
		assertThat(timer.discard(t2)).isFalse();
		TimeoutRecord tr2b = TimeoutRecord.forApp("testing purposes");
		timer.accept(t2, tr2b);
		assertThat(tr2b.getExpiredTimer()).isNull();
		}
		}

		/**
		* Return the dump string.
		*/