From 00ba9e8c24cc8bfe78042138a0e81f0e6fe56e9e Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Fri, 24 Jun 2022 16:51:15 +0000
Subject: [PATCH] BBQ: Attach calling thread to jvm if needed

When BBQ is destroyed from a native thread created by
the app, getEnv fails because the calling thread is not
attached to the jvm. To fix this, check the result when
getting the env from the jvm and attach the current
thread if needed.

Test: app in bug doesnt crash when resumed
Fixes: 236780458
Change-Id: Ib82b9b372167df60ad230ac309099db9f4a1a1fc
---
 .../jni/android_graphics_BLASTBufferQueue.cpp | 21 +++++++++----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/core/jni/android_graphics_BLASTBufferQueue.cpp b/core/jni/android_graphics_BLASTBufferQueue.cpp
index 4af28ea243611..1520ea5c6831f 100644
--- a/core/jni/android_graphics_BLASTBufferQueue.cpp
+++ b/core/jni/android_graphics_BLASTBufferQueue.cpp
@@ -41,7 +41,12 @@ struct {
 
 static JNIEnv* getenv(JavaVM* vm) {
     JNIEnv* env;
-    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
+    auto result = vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6);
+    if (result == JNI_EDETACHED) {
+        if (vm->AttachCurrentThreadAsDaemon(&env, nullptr) != JNI_OK) {
+            LOG_ALWAYS_FATAL("Failed to AttachCurrentThread!");
+        }
+    } else if (result != JNI_OK) {
         LOG_ALWAYS_FATAL("Failed to get JNIEnv for JavaVM: %p", vm);
     }
     return env;
@@ -60,28 +65,22 @@ public:
     }
 
     ~TransactionHangCallbackWrapper() {
-        if (mTransactionHangObject) {
-            getenv()->DeleteGlobalRef(mTransactionHangObject);
+        if (mTransactionHangObject != nullptr) {
+            getenv(mVm)->DeleteGlobalRef(mTransactionHangObject);
             mTransactionHangObject = nullptr;
         }
     }
 
     void onTransactionHang(bool isGpuHang) {
         if (mTransactionHangObject) {
-            getenv()->CallVoidMethod(mTransactionHangObject,
-                                     gTransactionHangCallback.onTransactionHang, isGpuHang);
+            getenv(mVm)->CallVoidMethod(mTransactionHangObject,
+                                        gTransactionHangCallback.onTransactionHang, isGpuHang);
         }
     }
 
 private:
     JavaVM* mVm;
     jobject mTransactionHangObject;
-
-    JNIEnv* getenv() {
-        JNIEnv* env;
-        mVm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6);
-        return env;
-    }
 };
 
 static jlong nativeCreate(JNIEnv* env, jclass clazz, jstring jName,