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Commit 7f0b453b authored by Christopher Tate's avatar Christopher Tate Committed by The Android Automerger
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Eliminate race condition around backup completion + resumption 

Ensure that the callback always sees the current-operation state in sync
with the various other bits of internal backup-operation state.  Previously
only the current-operation state was managed inside the critical section;
this resulted in a slim race window where a callback could see an ongoing
operation as still valid, but after the internal state on which that
operation depended had already been cleared.

Bug 17931760

Change-Id: Ia032668e7a9d22f1029c57fc98db9e86484d5719
parent 9dc533f0

services/backup/java/com/android/server/backup/BackupManagerService.java

+4 −1
Original line number Diff line number Diff line
@@ -2855,9 +2855,12 @@ public class BackupManagerService extends IBackupManager.Stub { 
            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