From 6bd77ab542d19efbb1907c08b83d34cbeedc9cfe Mon Sep 17 00:00:00 2001
From: Jing Ji <jji@google.com>
Date: Tue, 20 Aug 2019 16:49:08 -0700
Subject: [PATCH] Proper fix for the LRU IndexOutOfBoundsException

Previous fix for b/126427214 would result that the target process
being inserted gets falling out of the "Activities" section. A
proper fix should be in the remove LRU process part.

Also fixed an issue during the update of client activities:
when the sub proc should be sitting at the end of the group,
ineeded it's getting inserted to a position before end index
which could be pointing to a different process group, therefore
the end result would be "mixed" group.

Bug: 139765319
Test: atest CtsAppTestCases:ServiceTest\#testActivityServiceBindingLru
      manual: launch many apps and check the activity lru dump.

Change-Id: Ic56e38854837a07b8dabd1d19ba35eb1bfe4fd7a
Merged-In: Ic56e38854837a07b8dabd1d19ba35eb1bfe4fd7a
---
 .../java/com/android/server/am/ProcessList.java   | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/services/core/java/com/android/server/am/ProcessList.java b/services/core/java/com/android/server/am/ProcessList.java
index b399971d1ad5d..838e7d3c02086 100644
--- a/services/core/java/com/android/server/am/ProcessList.java
+++ b/services/core/java/com/android/server/am/ProcessList.java
@@ -2094,10 +2094,10 @@ public final class ProcessList {
                     }
                 }
             }
-            if (lrui <= mLruProcessActivityStart) {
+            if (lrui < mLruProcessActivityStart) {
                 mLruProcessActivityStart--;
             }
-            if (lrui <= mLruProcessServiceStart) {
+            if (lrui < mLruProcessServiceStart) {
                 mLruProcessServiceStart--;
             }
             mLruProcesses.remove(lrui);
@@ -2629,7 +2629,7 @@ public final class ProcessList {
                         if (!moved) {
                             // Goes to the end of the group.
                             mLruProcesses.remove(i);
-                            mLruProcesses.add(endIndex - 1, subProc);
+                            mLruProcesses.add(endIndex, subProc);
                             if (DEBUG_LRU) Slog.d(TAG_LRU,
                                     "Moving " + subProc
                                             + " from position " + i + " to end of group @ "
@@ -2874,15 +2874,6 @@ public final class ProcessList {
                     pos--;
                 }
                 mLruProcesses.add(pos, app);
-                if (pos == mLruProcessActivityStart) {
-                    mLruProcessActivityStart++;
-                }
-                if (pos == mLruProcessServiceStart) {
-                    // Unless {@code #hasService} is implemented, currently the starting position
-                    // for activity and service are the same, so the incoming position may equal to
-                    // the starting position of service.
-                    mLruProcessServiceStart++;
-                }
                 // If this process is part of a group, need to pull up any other processes
                 // in that group to be with it.
                 int endIndex = pos - 1;