From b496a7ef11f6bc6bc70db20b4c66d02c07718216 Mon Sep 17 00:00:00 2001
From: sspitsyn <unknown>
Date: Sun, 15 Jan 2017 02:07:05 -0800
Subject: [PATCH] 8034249: need more workarounds for suspend equivalent
 condition issue Summary: Collect data at safepoint, do not rely on thread
 suspension Reviewed-by: dcubed, dholmes

---
 src/share/vm/prims/jvmtiEnv.cpp     | 24 +++++++++++++++---------
 src/share/vm/prims/jvmtiEnvBase.hpp | 20 ++++++++++++++------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/share/vm/prims/jvmtiEnv.cpp b/src/share/vm/prims/jvmtiEnv.cpp
index 0c92c8876..98624be32 100644
--- a/src/share/vm/prims/jvmtiEnv.cpp
+++ b/src/share/vm/prims/jvmtiEnv.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1000,8 +1000,9 @@ JvmtiEnv::GetOwnedMonitorInfo(JavaThread* java_thread, jint* owned_monitor_count
   GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list =
       new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jvmtiMonitorStackDepthInfo*>(1, true);
 
-  uint32_t debug_bits = 0;
-  if (is_thread_fully_suspended(java_thread, true, &debug_bits)) {
+  // It is only safe to perform the direct operation on the current
+  // thread. All other usage needs to use a vm-safepoint-op for safety.
+  if (java_thread == calling_thread) {
     err = get_owned_monitors(calling_thread, java_thread, owned_monitors_list);
   } else {
     // JVMTI get monitors info at safepoint. Do not require target thread to
@@ -1045,8 +1046,9 @@ JvmtiEnv::GetOwnedMonitorStackDepthInfo(JavaThread* java_thread, jint* monitor_i
   GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list =
          new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jvmtiMonitorStackDepthInfo*>(1, true);
 
-  uint32_t debug_bits = 0;
-  if (is_thread_fully_suspended(java_thread, true, &debug_bits)) {
+  // It is only safe to perform the direct operation on the current
+  // thread. All other usage needs to use a vm-safepoint-op for safety.
+  if (java_thread == calling_thread) {
     err = get_owned_monitors(calling_thread, java_thread, owned_monitors_list);
   } else {
     // JVMTI get owned monitors info at safepoint. Do not require target thread to
@@ -1087,9 +1089,11 @@ JvmtiEnv::GetOwnedMonitorStackDepthInfo(JavaThread* java_thread, jint* monitor_i
 jvmtiError
 JvmtiEnv::GetCurrentContendedMonitor(JavaThread* java_thread, jobject* monitor_ptr) {
   jvmtiError err = JVMTI_ERROR_NONE;
-  uint32_t debug_bits = 0;
   JavaThread* calling_thread  = JavaThread::current();
-  if (is_thread_fully_suspended(java_thread, true, &debug_bits)) {
+
+  // It is only safe to perform the direct operation on the current
+  // thread. All other usage needs to use a vm-safepoint-op for safety.
+  if (java_thread == calling_thread) {
     err = get_current_contended_monitor(calling_thread, java_thread, monitor_ptr);
   } else {
     // get contended monitor information at safepoint.
@@ -1298,8 +1302,10 @@ JvmtiEnv::GetThreadGroupChildren(jthreadGroup group, jint* thread_count_ptr, jth
 jvmtiError
 JvmtiEnv::GetStackTrace(JavaThread* java_thread, jint start_depth, jint max_frame_count, jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
   jvmtiError err = JVMTI_ERROR_NONE;
-  uint32_t debug_bits = 0;
-  if (is_thread_fully_suspended(java_thread, true, &debug_bits)) {
+
+  // It is only safe to perform the direct operation on the current
+  // thread. All other usage needs to use a vm-safepoint-op for safety.
+  if (java_thread == JavaThread::current()) {
     err = get_stack_trace(java_thread, start_depth, max_frame_count, frame_buffer, count_ptr);
   } else {
     // JVMTI get stack trace at safepoint. Do not require target thread to
diff --git a/src/share/vm/prims/jvmtiEnvBase.hpp b/src/share/vm/prims/jvmtiEnvBase.hpp
index 084e19b45..e8c23b10f 100644
--- a/src/share/vm/prims/jvmtiEnvBase.hpp
+++ b/src/share/vm/prims/jvmtiEnvBase.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -356,8 +356,12 @@ public:
   }
   VMOp_Type type() const { return VMOp_GetOwnedMonitorInfo; }
   void doit() {
-    ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread, _java_thread,
-                                                         _owned_monitors_list);
+    _result = JVMTI_ERROR_THREAD_NOT_ALIVE;
+    if (Threads::includes(_java_thread) && !_java_thread->is_exiting()
+                                        && _java_thread->threadObj() != NULL) {
+      _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread, _java_thread,
+                                                            _owned_monitors_list);
+    }
   }
   jvmtiError result() { return _result; }
 };
@@ -439,9 +443,13 @@ public:
   jvmtiError result() { return _result; }
   VMOp_Type type() const { return VMOp_GetStackTrace; }
   void doit() {
-    _result = ((JvmtiEnvBase *)_env)->get_stack_trace(_java_thread,
-                                                      _start_depth, _max_count,
-                                                      _frame_buffer, _count_ptr);
+    _result = JVMTI_ERROR_THREAD_NOT_ALIVE;
+    if (Threads::includes(_java_thread) && !_java_thread->is_exiting()
+                                        && _java_thread->threadObj() != NULL) {
+      _result = ((JvmtiEnvBase *)_env)->get_stack_trace(_java_thread,
+                                                        _start_depth, _max_count,
+                                                        _frame_buffer, _count_ptr);
+    }
   }
 };
 
-- 
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