am 040d89bb: Merge "Eliminate race condition around backup completion + resumption" into lmp-dev

* commit '040d89bb0a4563d93073b7a27b3f201ce11dcf58':
  Eliminate race condition around backup completion + resumption
diff --git a/services/backup/java/com/android/server/backup/BackupManagerService.java b/services/backup/java/com/android/server/backup/BackupManagerService.java
index 60801fb..fea1a7a 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerService.java
@@ -2855,9 +2855,12 @@
             try { if (mSavedState != null) mSavedState.close(); } catch (IOException e) {}
             try { if (mBackupData != null) mBackupData.close(); } catch (IOException e) {}
             try { if (mNewState != null) mNewState.close(); } catch (IOException e) {}
-            mSavedState = mBackupData = mNewState = null;
             synchronized (mCurrentOpLock) {
+                // Current-operation callback handling requires the validity of these various
+                // bits of internal state as an invariant of the operation still being live.
+                // This means we make sure to clear all of the state in unison inside the lock.
                 mCurrentOperations.clear();
+                mSavedState = mBackupData = mNewState = null;
             }
 
             // If this was a pseudopackage there's no associated Activity Manager state