src/hotspot/share/oops/weakHandle.cpp
author coleenp
Wed, 18 Apr 2018 18:43:04 -0400
changeset 49824 e242740a92b8
parent 49738 a7bc87a63dd8
child 50445 bd6b78feb6a3
permissions -rw-r--r--
8201556: Disallow reading oops in ClassLoaderData if unloading Summary: Move class_loader oop to an OopHandle, and assert that holder is alive when getting class_loader. Reviewed-by: kbarrett, adinn
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/*
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 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "classfile/systemDictionary.hpp"
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#include "gc/shared/oopStorage.hpp"
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#include "oops/access.inline.hpp"
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#include "oops/oop.hpp"
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#include "oops/weakHandle.inline.hpp"
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#include "utilities/debug.hpp"
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#include "utilities/ostream.hpp"
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template <> OopStorage* WeakHandle<vm_class_loader_data>::get_storage() {
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  return SystemDictionary::vm_weak_oop_storage();
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}
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template <WeakHandleType T>
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WeakHandle<T> WeakHandle<T>::create(Handle obj) {
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  assert(obj() != NULL, "no need to create weak null oop");
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  oop* oop_addr = get_storage()->allocate();
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  if (oop_addr == NULL) {
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    vm_exit_out_of_memory(sizeof(oop*), OOM_MALLOC_ERROR, "Unable to create new weak oop handle in OopStorage");
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  }
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  // Create WeakHandle with address returned and store oop into it.
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  RootAccess<ON_PHANTOM_OOP_REF>::oop_store(oop_addr, obj());
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  return WeakHandle(oop_addr);
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}
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template <WeakHandleType T>
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void WeakHandle<T>::release() const {
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  // Only release if the pointer to the object has been created.
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  if (_obj != NULL) {
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    // Clear the WeakHandle.  For race in creating ClassLoaderData, we can release this
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    // WeakHandle before it is cleared by GC.
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    RootAccess<ON_PHANTOM_OOP_REF>::oop_store(_obj, (oop)NULL);
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    get_storage()->release(_obj);
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  }
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}
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template <WeakHandleType T>
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void WeakHandle<T>::print() const { print_on(tty); }
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template <WeakHandleType T>
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void WeakHandle<T>::print_on(outputStream* st) const {
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  st->print("WeakHandle: " PTR_FORMAT, p2i(peek()));
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}
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// Provide instantiation.
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template class WeakHandle<vm_class_loader_data>;
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