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Commit 8d231b4c authored by Zimuzo's avatar Zimuzo
Browse files

Fix handling multiple staged rollback sessions ready signal 

After we stage a session for rollback, we need to wait for the
session to be ready and then reboot. To ensure we don't miss the
ready signal, we register a BroadcastReceiver to listen to session changes
and also check for session ready right away. This caused a race condition
where we may handle post-ready twice. This caused a crash because we
attempt to unregister the receiver twice, it's also a problem because
we could log the same event twice.

Now, we store the rollback ids we are about to handle and ensure we never
handle post-ready more than once.

Test: Manual test && atest StagedRollbackTest
Bug: 132866890
Change-Id: I5187ff20fb83b29f7a00a28bf6ad8105ca4f0067
parent 0ab51714

services/core/java/com/android/server/rollback/RollbackPackageHealthObserver.java

+22 −2
Original line number Diff line number Diff line
@@ -34,10 +34,12 @@ import android.os.HandlerThread; 
import android.os.PowerManager;

import android.os.SystemProperties;

import android.text.TextUtils;

import android.util.ArraySet;

import android.util.Slog;

import android.util.StatsLog;



import com.android.internal.R;

import com.android.internal.annotations.GuardedBy;

import com.android.server.PackageWatchdog;

import com.android.server.PackageWatchdog.PackageHealthObserver;

import com.android.server.PackageWatchdog.PackageHealthObserverImpact;
@@ -50,6 +52,7 @@ import java.io.IOException; 
import java.io.PrintWriter;

import java.util.Collections;

import java.util.List;

import java.util.Set;

import java.util.concurrent.TimeUnit;



/**
@@ -71,6 +74,9 @@ public final class RollbackPackageHealthObserver implements PackageHealthObserve 
    private final Context mContext;

    private final Handler mHandler;

    private final File mLastStagedRollbackIdFile;

    // Staged rollback ids that have been committed but their session is not yet ready

    @GuardedBy("mPendingStagedRollbackIds")

    private final Set<Integer> mPendingStagedRollbackIds = new ArraySet<>();

    // this field is initialized in the c'tor and then only accessed from mHandler thread, so

    // no need to guard with a lock

    private long mNumberOfNativeCrashPollsRemaining;
@@ -120,6 +126,9 @@ public final class RollbackPackageHealthObserver implements PackageHealthObserve 
            if (status == RollbackManager.STATUS_SUCCESS) {

                if (rollback.isStaged()) {

                    int rollbackId = rollback.getRollbackId();

                    synchronized (mPendingStagedRollbackIds) {

                        mPendingStagedRollbackIds.add(rollbackId);

                    }

                    BroadcastReceiver listener =

                            listenForStagedSessionReady(rollbackManager, rollbackId,

                                    moduleMetadataPackage);
@@ -289,14 +298,15 @@ public final class RollbackPackageHealthObserver implements PackageHealthObserve 
                    && (sessionId != PackageInstaller.SessionInfo.INVALID_ID)) {

                PackageInstaller.SessionInfo sessionInfo =

                        packageInstaller.getSessionInfo(sessionId);

                if (sessionInfo.isStagedSessionReady()) {

                if (sessionInfo.isStagedSessionReady() && markStagedSessionHandled(rollbackId)) {

                    mContext.unregisterReceiver(listener);

                    saveLastStagedRollbackId(rollbackId);

                    logEvent(moduleMetadataPackage,

                            StatsLog

                            .WATCHDOG_ROLLBACK_OCCURRED__ROLLBACK_TYPE__ROLLBACK_BOOT_TRIGGERED);

                    mContext.getSystemService(PowerManager.class).reboot("Rollback staged install");

                } else if (sessionInfo.isStagedSessionFailed()) {

                } else if (sessionInfo.isStagedSessionFailed()

                        && markStagedSessionHandled(rollbackId)) {

                    logEvent(moduleMetadataPackage,

                            StatsLog.WATCHDOG_ROLLBACK_OCCURRED__ROLLBACK_TYPE__ROLLBACK_FAILURE);

                    mContext.unregisterReceiver(listener);
@@ -305,6 +315,16 @@ public final class RollbackPackageHealthObserver implements PackageHealthObserve 
        }

    }



    /**

     * Returns {@code true} if staged session associated with {@code rollbackId} was marked

     * as handled, {@code false} if already handled.

     */

    private boolean markStagedSessionHandled(int rollbackId) {

        synchronized (mPendingStagedRollbackIds) {

            return mPendingStagedRollbackIds.remove(rollbackId);

        }

    }



    private void saveLastStagedRollbackId(int stagedRollbackId) {

        try {

            FileOutputStream fos = new FileOutputStream(mLastStagedRollbackIdFile);