Fix a deadlock involving BatteryService.

The PowerManager may call into the BatteryService while
holding its locks.  We need to be careful that the BatteryService
doesn't call into other services, particularly the ActivityManager
while holding its own locks.

Bug: 7298218
Change-Id: Ibf8ab13224f204a9857825265e864f93583bce8e

Author: Jeff Brown

services/java/com/android/server/BatteryService.java

@@ -27,6 +27,7 @@
 import android.os.BatteryManager;
 import android.os.Binder;
 import android.os.FileUtils;
+import android.os.Handler;
 import android.os.IBinder;
 import android.os.DropBoxManager;
 import android.os.RemoteException;
@@ -66,6 +67,14 @@
  * <p>&quot;temperature&quot; - int, current battery temperature in tenths of
  * a degree Centigrade</p>
  * <p>&quot;technology&quot; - String, the type of battery installed, e.g. "Li-ion"</p>
+ *
+ * <p>
+ * The battery service may be called by the power manager while holding its locks so
+ * we take care to post all outcalls into the activity manager to a handler.
+ *
+ * FIXME: Ideally the power manager would perform all of its calls into the battery
+ * service asynchronously itself.
+ * </p>
  */
 public final class BatteryService extends Binder {
     private static final String TAG = BatteryService.class.getSimpleName();
@@ -89,6 +98,7 @@ public final class BatteryService extends Binder {
 
     private final Context mContext;
     private final IBatteryStats mBatteryStats;
+    private final Handler mHandler;
 
     private final Object mLock = new Object();
 
@@ -137,6 +147,7 @@ public final class BatteryService extends Binder {
 
     public BatteryService(Context context, LightsService lights) {
         mContext = context;
+        mHandler = new Handler(true /*async*/);
         mLed = new Led(context, lights);
         mBatteryStats = BatteryStatsService.getService();
 
@@ -228,25 +239,37 @@ public boolean isBatteryLow() {
     private void shutdownIfNoPowerLocked() {
         // shut down gracefully if our battery is critically low and we are not powered.
         // wait until the system has booted before attempting to display the shutdown dialog.
-        if (mBatteryLevel == 0 && !isPoweredLocked(BatteryManager.BATTERY_PLUGGED_ANY)
-                && ActivityManagerNative.isSystemReady()) {
-            Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
-            intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
-            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-            mContext.startActivityAsUser(intent, UserHandle.CURRENT);
+        if (mBatteryLevel == 0 && !isPoweredLocked(BatteryManager.BATTERY_PLUGGED_ANY)) {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    if (ActivityManagerNative.isSystemReady()) {
+                        Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
+                        intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
+                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+                        mContext.startActivityAsUser(intent, UserHandle.CURRENT);
+                    }
+                }
+            });
         }
     }
 
     private void shutdownIfOverTempLocked() {
         // shut down gracefully if temperature is too high (> 68.0C by default)
         // wait until the system has booted before attempting to display the
         // shutdown dialog.
-        if (mBatteryTemperature > mShutdownBatteryTemperature
-                && ActivityManagerNative.isSystemReady()) {
-            Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
-            intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
-            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-            mContext.startActivityAsUser(intent, UserHandle.CURRENT);
+        if (mBatteryTemperature > mShutdownBatteryTemperature) {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    if (ActivityManagerNative.isSystemReady()) {
+                        Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
+                        intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
+                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+                        mContext.startActivityAsUser(intent, UserHandle.CURRENT);
+                    }
+                }
+            });
         }
     }
 
@@ -373,25 +396,47 @@ private void processValuesLocked() {
             // Separate broadcast is sent for power connected / not connected
             // since the standard intent will not wake any applications and some
             // applications may want to have smart behavior based on this.
-            Intent statusIntent = new Intent();
-            statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
             if (mPlugType != 0 && mLastPlugType == 0) {
-                statusIntent.setAction(Intent.ACTION_POWER_CONNECTED);
-                mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                mHandler.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        Intent statusIntent = new Intent(Intent.ACTION_POWER_CONNECTED);
+                        statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                    }
+                });
             }
             else if (mPlugType == 0 && mLastPlugType != 0) {
-                statusIntent.setAction(Intent.ACTION_POWER_DISCONNECTED);
-                mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                mHandler.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        Intent statusIntent = new Intent(Intent.ACTION_POWER_DISCONNECTED);
+                        statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                    }
+                });
             }
 
             if (sendBatteryLow) {
                 mSentLowBatteryBroadcast = true;
-                statusIntent.setAction(Intent.ACTION_BATTERY_LOW);
-                mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                mHandler.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        Intent statusIntent = new Intent(Intent.ACTION_BATTERY_LOW);
+                        statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                    }
+                });
             } else if (mSentLowBatteryBroadcast && mLastBatteryLevel >= mLowBatteryCloseWarningLevel) {
                 mSentLowBatteryBroadcast = false;
-                statusIntent.setAction(Intent.ACTION_BATTERY_OKAY);
-                mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                mHandler.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        Intent statusIntent = new Intent(Intent.ACTION_BATTERY_OKAY);
+                        statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
+                    }
+                });
             }
 
             // Update the battery LED
@@ -416,7 +461,7 @@ else if (mPlugType == 0 && mLastPlugType != 0) {
 
     private void sendIntentLocked() {
         //  Pack up the values and broadcast them to everyone
-        Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);
+        final Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);
         intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY
                 | Intent.FLAG_RECEIVER_REPLACE_PENDING);
 
@@ -446,7 +491,12 @@ private void sendIntentLocked() {
                     ", icon:" + icon  + ", invalid charger:" + mInvalidCharger);
         }
 
-        ActivityManagerNative.broadcastStickyIntent(intent, null, UserHandle.USER_ALL);
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                ActivityManagerNative.broadcastStickyIntent(intent, null, UserHandle.USER_ALL);
+            }
+        });
     }
 
     private void logBatteryStatsLocked() {