commit 8ea9b3711a5cc6c2d9ec4fe1e57e8c36fc62bced
author Alex Light <allight@google.com> Wed Sep 04 15:52:41 2019 -0700
committer Alex Light <allight@google.com> Wed Sep 04 23:02:16 2019 +0000
tree 77ec6a1b7c2864f8e05f4a35d92abf0689b6d837
parent 9d4fb714d84031f136bd1d5f0b70d53e710e5abf

Use j.l.ThreadGroup class directly for GetThreadGroupInfo

We were using the class of the input to GetThreadGroupInfo in some
situations. This could lead to us reading the wrong field or not
finding expected fields. Change to always directly use the
j.l.ThreadGroup class from WellKnownClasses. Also use some handles in
this function.

Test: ./test.py --host
Bug: 140521090
Change-Id: I3560662718311ccc0fa9b906f178407350ce9960

openjdkjvmti/ti_threadgroup.cc

diff --git a/openjdkjvmti/ti_threadgroup.cc b/openjdkjvmti/ti_threadgroup.cc
index e17e61f..f2e5c90 100644
--- a/openjdkjvmti/ti_threadgroup.cc
+++ b/openjdkjvmti/ti_threadgroup.cc
@@ -99,7 +99,10 @@
     return ERR(INVALID_THREAD_GROUP);
   }
 
-  art::ObjPtr<art::mirror::Object> obj = soa.Decode<art::mirror::Object>(group);
+  art::StackHandleScope<2> hs(soa.Self());
+  art::Handle<art::mirror::Class> tg_class(
+      hs.NewHandle(soa.Decode<art::mirror::Class>(art::WellKnownClasses::java_lang_ThreadGroup)));
+  art::Handle<art::mirror::Object> obj(hs.NewHandle(soa.Decode<art::mirror::Object>(group)));
 
   // Do the name first. It's the only thing that can fail.
   {
@@ -107,7 +110,7 @@
         art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_name);
     CHECK(name_field != nullptr);
     art::ObjPtr<art::mirror::String> name_obj =
-        art::ObjPtr<art::mirror::String>::DownCast(name_field->GetObject(obj));
+        art::ObjPtr<art::mirror::String>::DownCast(name_field->GetObject(obj.Get()));
     std::string tmp_str;
     const char* tmp_cstr;
     if (name_obj == nullptr) {
@@ -129,7 +132,7 @@
     art::ArtField* parent_field =
         art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_parent);
     CHECK(parent_field != nullptr);
-    art::ObjPtr<art::mirror::Object> parent_group = parent_field->GetObject(obj);
+    art::ObjPtr<art::mirror::Object> parent_group = parent_field->GetObject(obj.Get());
     info_ptr->parent = parent_group == nullptr
                            ? nullptr
                            : soa.AddLocalReference<jthreadGroup>(parent_group);
@@ -137,16 +140,16 @@
 
   // Max priority.
   {
-    art::ArtField* prio_field = obj->GetClass()->FindDeclaredInstanceField("maxPriority", "I");
+    art::ArtField* prio_field = tg_class->FindDeclaredInstanceField("maxPriority", "I");
     CHECK(prio_field != nullptr);
-    info_ptr->max_priority = static_cast<jint>(prio_field->GetInt(obj));
+    info_ptr->max_priority = static_cast<jint>(prio_field->GetInt(obj.Get()));
   }
 
   // Daemon.
   {
-    art::ArtField* daemon_field = obj->GetClass()->FindDeclaredInstanceField("daemon", "Z");
+    art::ArtField* daemon_field = tg_class->FindDeclaredInstanceField("daemon", "Z");
     CHECK(daemon_field != nullptr);
-    info_ptr->is_daemon = daemon_field->GetBoolean(obj) == 0 ? JNI_FALSE : JNI_TRUE;
+    info_ptr->is_daemon = daemon_field->GetBoolean(obj.Get()) == 0 ? JNI_FALSE : JNI_TRUE;
   }
 
   return ERR(NONE);