linkToDeath exception cause system server crash

java.util.NoSuchElementException: Death link does not exist

when linkToDeath has remote exception, unlinkToDeath will fail and
throw NoSuchElementException, catch it in AbstractAccessibilityServiceConnection
to avoid system server crash.

Bug: 157580692
Test: manual
Change-Id: I42ce3a458e04539d76555679279d1368e0c61ae0

2 files changed, 31 insertions, 1 deletions

diff --git a/diff b/diff
new file mode 100644
index 000000000000..5c75d88e6789
--- /dev/null
+++ b/diff
@@ -0,0 +1,25 @@
+diff --git a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
+index fc43882..832dc91 100644
+--- a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
++++ b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
+@@ -67,6 +67,7 @@ import java.util.Arrays;
+ import java.util.HashSet;
+ import java.util.List;
+ import java.util.Set;
++import java.util.NoSuchElementException;
+ 
+ /**
+  * This class represents an accessibility client - either an AccessibilityService or a UiAutomation.
+@@ -978,7 +979,11 @@ abstract class AbstractAccessibilityServiceConnection extends IAccessibilityServ
+                 /* ignore */
+         }
+         if (mService != null) {
+-            mService.unlinkToDeath(this, 0);
++            try {
++                mService.unlinkToDeath(this, 0);
++            }catch(NoSuchElementException e) {
++                Slog.e(LOG_TAG, "Failed unregistering death link");
++            }
+             mService = null;
+         }
+ 
diff --git a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
index 6b852adce0f1..40a2816ee7de 100644
--- a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
+++ b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
@@ -90,6 +90,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.Set;
 
 /**
@@ -1179,7 +1180,11 @@ abstract class AbstractAccessibilityServiceConnection extends IAccessibilityServ
                 /* ignore */
         }
         if (mService != null) {
-            mService.unlinkToDeath(this, 0);
+            try {
+                mService.unlinkToDeath(this, 0);
+            } catch (NoSuchElementException e) {
+                Slog.e(LOG_TAG, "Failed unregistering death link");
+            }
             mService = null;
         }