From 9e80c7bb6a53d2a4ba1df348ea36b43707167840 Mon Sep 17 00:00:00 2001
From: David Su <dysu@google.com>
Date: Tue, 30 Jun 2020 17:52:18 -0700
Subject: Fix quickly toggling airplane mode on then off could leave Wifi
 disabled

If Wifi is enabled, and we toggle airplane mode on then off quickly,
afterwards wifi could be stuck in the disabled state, even though the
expected behavior is that Wifi return to enabled state. This is due to
a race between CMD_AIRPLANE_TOGGLED and ClientListener.onStopped().

To fix this, defer CMD_AIRPLANE_TOGGLED if we are still processing
a previous CMD_AIRPLANE_TOGGLED.

Bug: 160105640
Test: atest ActiveModeWardenTest
Test: manually toggle airplane mode on then off quickly while wifi is enabled
Change-Id: I8f40dbba0be170a5eca38f0221b4b722cb4b96a4
---
 .../com/android/server/wifi/ActiveModeWarden.java  | 12 +++++--
 .../android/server/wifi/ActiveModeWardenTest.java  | 37 ++++++++++++++++++++++
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/service/java/com/android/server/wifi/ActiveModeWarden.java b/service/java/com/android/server/wifi/ActiveModeWarden.java
index e0a0a3d29..cf54e328b 100644
--- a/service/java/com/android/server/wifi/ActiveModeWarden.java
+++ b/service/java/com/android/server/wifi/ActiveModeWarden.java
@@ -850,6 +850,9 @@ public class ActiveModeWarden {
         }
 
         class EnabledState extends BaseState {
+
+            private boolean mIsDisablingDueToAirplaneMode;
+
             @Override
             public void enter() {
                 log("EnabledState.enter()");
@@ -857,6 +860,7 @@ public class ActiveModeWarden {
                 if (!hasAnyModeManager()) {
                     Log.e(TAG, "Entered EnabledState, but no active mode managers");
                 }
+                mIsDisablingDueToAirplaneMode = false;
             }
 
             @Override
@@ -894,11 +898,15 @@ public class ActiveModeWarden {
                     case CMD_AIRPLANE_TOGGLED:
                         // airplane mode toggled on is handled in the default state
                         if (mSettingsStore.isAirplaneModeOn()) {
+                            mIsDisablingDueToAirplaneMode = true;
                             return NOT_HANDLED;
                         } else {
-                            if (hasAnyModeManagerStopping()) {
-                                // previous airplane mode toggle on is being processed, defer the
+                            if (mIsDisablingDueToAirplaneMode) {
+                                // Previous airplane mode toggle on is being processed, defer the
                                 // message toggle off until previous processing is completed.
+                                // Once previous airplane mode toggle is complete, we should
+                                // transition to DisabledState. There, we will process the deferred
+                                // airplane mode toggle message to disable airplane mode.
                                 deferMessage(msg);
                             } else {
                                 // when airplane mode is toggled off, but wifi is on, we can keep it
diff --git a/tests/wifitests/src/com/android/server/wifi/ActiveModeWardenTest.java b/tests/wifitests/src/com/android/server/wifi/ActiveModeWardenTest.java
index ceaf76dc8..8294bdb04 100644
--- a/tests/wifitests/src/com/android/server/wifi/ActiveModeWardenTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/ActiveModeWardenTest.java
@@ -2239,6 +2239,43 @@ public class ActiveModeWardenTest extends WifiBaseTest {
         assertInEnabledState();
     }
 
+    @Test
+    public void airplaneModeToggleOffIsDeferredWhileProcessingToggleOnWithOneModeManager2()
+            throws Exception {
+        enterClientModeActiveState();
+        assertInEnabledState();
+
+        // APM toggle on
+        assertWifiShutDown(() -> {
+            when(mSettingsStore.isAirplaneModeOn()).thenReturn(true);
+            mActiveModeWarden.airplaneModeToggled();
+            mLooper.dispatchAll();
+        });
+
+
+        // APM toggle off before the stop is complete.
+        assertInEnabledState();
+        when(mClientModeManager.isStopping()).thenReturn(true);
+        when(mSettingsStore.isAirplaneModeOn()).thenReturn(false);
+        mActiveModeWarden.airplaneModeToggled();
+        // This test is identical to
+        // airplaneModeToggleOffIsDeferredWhileProcessingToggleOnWithOneModeManager, except the
+        // dispatchAll() here is removed. There could be a race between airplaneModeToggled and
+        // mClientListener.onStopped(). See b/160105640#comment5.
+
+        mClientListener.onStopped();
+        mLooper.dispatchAll();
+
+        verify(mClientModeManager, times(2)).start();
+        verify(mClientModeManager, times(2)).setRole(ROLE_CLIENT_PRIMARY);
+
+        mClientListener.onStarted();
+        mLooper.dispatchAll();
+
+        // We should be back to enabled state.
+        assertInEnabledState();
+    }
+
     @Test
     public void airplaneModeToggleOffIsDeferredWhileProcessingToggleOnWithTwoModeManager()
             throws Exception {
-- 
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