From 885bec8d86d8a4a21ae92c02c8c77339a9b3c0e1 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer@google.com>
Date: Thu, 19 Jan 2023 17:55:52 -0800
Subject: [PATCH] [MTE] upgrade apps from async to sync mode on debug builds

These builds are slower anyway, as they enabled MTE sync mode (with
stack trace collection) on the whole platform. To make debugging easier,
also upgrade apps that enable MTE to sync mode.

Bug: 266056313
Test: app-memtag_async-release.apk crashes with MTESERR
Change-Id: I1d6d57c236a54cda2d5d61083f1bdf701c65185e
---
 core/java/com/android/internal/os/Zygote.java | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index deafd19e866f0..d9cb72a5daa15 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -1328,6 +1328,15 @@ public final class Zygote {
             level = MEMORY_TAG_LEVEL_NONE;
         }
 
+        // If we requested "sync" mode for the whole platform, upgrade mode for apps that enable
+        // MTE.
+        // This makes debugging a lot easier.
+        if (level == MEMORY_TAG_LEVEL_ASYNC
+                && (Build.IS_USERDEBUG || Build.IS_ENG)
+                && "sync".equals(SystemProperties.get("persist.arm64.memtag.default"))) {
+            level = MEMORY_TAG_LEVEL_SYNC;
+        }
+
         return level;
     }