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8187577: JVM crash during gc doing concurrent marking

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Inform G1's SATB that a klass has been resurrected and it should not be unloaded

Reviewed-by: coleenp, tschatzl, kbarrett
This commit is contained in:
Poonam Bajaj 2018-02-07 21:53:38 +00:00
parent eeaf00be4f
commit 4779c85b46
1 changed files with 19 additions and 1 deletions

20
src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2018, 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
@ -29,6 +29,9 @@
#include "prims/jvmtiGetLoadedClasses.hpp"
#include "runtime/thread.hpp"
#include "utilities/stack.inline.hpp"
#if INCLUDE_ALL_GCS
#include "gc/g1/g1SATBCardTableModRefBS.hpp"
#endif
// The closure for GetLoadedClasses
@ -38,6 +41,20 @@ private:
JvmtiEnv* _env;
Thread* _cur_thread;
// Tell the GC to keep this klass alive
static void ensure_klass_alive(oop o) {
// A klass that was previously considered dead can be looked up in the
// CLD/SD, and its _java_mirror or _class_loader can be stored in a root
// or a reachable object making it alive again. The SATB part of G1 needs
// to get notified about this potential resurrection, otherwise the marking
// might not find the object.
#if INCLUDE_ALL_GCS
if (UseG1GC && o != NULL) {
G1SATBCardTableModRefBS::enqueue(o);
}
#endif
}
public:
LoadedClassesClosure(Thread* thread, JvmtiEnv* env) : _cur_thread(thread), _env(env) {
assert(_cur_thread == Thread::current(), "must be current thread");
@ -46,6 +63,7 @@ public:
void do_klass(Klass* k) {
// Collect all jclasses
_classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, k->java_mirror())));
ensure_klass_alive(k->java_mirror());
}
int extract(jclass* result_list) {