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Commit 1b3b4827 authored by Sarah Chin's avatar Sarah Chin
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DataConnection fix race condition due to mApnSetting 

The race condition occurs when DataConnection calls clearSettings on the
DC thread while the main thread calls toStringSimple on the main thread.
DC#clearSettings sets mApnSetting to null, and toStringSimple calls
getNetworkCapabilities, which checks whether mApnSetting is null or not.
Fix the race condition by making both clearSettings and toStringSimple
synchronized, so mApnSetting will be set to null and toStringSimple will
run afterwards instead of at the same time.

Test: atest DataConnectionTest
Fix: 195317191
Change-Id: I85ca70494f0b2663d3344f2a7c3e6e9a68a57ca1
parent 8a294d8e

src/java/com/android/internal/telephony/dataconnection/DataConnection.java

+2 −2
Original line number Diff line number Diff line
@@ -1324,7 +1324,7 @@ public class DataConnection extends StateMachine { 
    /**

     * Clear all settings called when entering mInactiveState.

     */

    private void clearSettings() {

    private synchronized void clearSettings() {

        if (DBG) log("clearSettings");



        mCreateTime = -1;
@@ -3830,7 +3830,7 @@ public class DataConnection extends StateMachine { 
    }



    /** Doesn't print mApnList of ApnContext's which would be recursive */

    public String toStringSimple() {

    public synchronized String toStringSimple() {

        return getName() + ": State=" + getCurrentState().getName()

                + " mApnSetting=" + mApnSetting + " RefCount=" + mApnContexts.size()

                + " mCid=" + mCid + " mCreateTime=" + mCreateTime