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8223177: Data race on JvmtiEnvBase::_tag_map in double-checked locking

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Add memory fences on accesses to JvmtiEnvBase::_tag_map

Reviewed-by: dholmes, jcbeyler, sspitsyn
This commit is contained in:
Man Cao 2019-04-30 18:44:41 -07:00
parent 75471b411d
commit 37be9ccd6c
2 changed files with 12 additions and 4 deletions
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10
src/hotspot/share/prims/jvmtiEnvBase.hpp
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@ -32,6 +32,7 @@
#include "oops/oopHandle.hpp"
#include "runtime/fieldDescriptor.hpp"
#include "runtime/frame.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/thread.hpp"
#include "runtime/vmOperations.hpp"
#include "utilities/growableArray.hpp"
@ -98,7 +99,7 @@ class JvmtiEnvBase : public CHeapObj<mtInternal> {
const void *_env_local_storage; // per env agent allocated data.
jvmtiEventCallbacks _event_callbacks;
jvmtiExtEventCallbacks _ext_event_callbacks;
JvmtiTagMap* _tag_map;
JvmtiTagMap* volatile _tag_map;
JvmtiEnvEventEnable _env_event_enable;
jvmtiCapabilities _current_capabilities;
jvmtiCapabilities _prohibited_capabilities;
@ -253,6 +254,13 @@ class JvmtiEnvBase : public CHeapObj<mtInternal> {
return _tag_map;
}
JvmtiTagMap* acquire_tag_map() {
return OrderAccess::load_acquire(&_tag_map);
}
void release_set_tag_map(JvmtiTagMap* tag_map) {
OrderAccess::release_store(&_tag_map, tag_map);
}
// return true if event is enabled globally or for any thread
// True only if there is a callback for it.

6
src/hotspot/share/prims/jvmtiTagMap.cpp
View File

@ -445,7 +445,7 @@ JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
_hashmap = new JvmtiTagHashmap();
// finally add us to the environment
((JvmtiEnvBase *)env)->set_tag_map(this);
((JvmtiEnvBase *)env)->release_set_tag_map(this);
}
@ -514,7 +514,7 @@ void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
// returns the tag map for the given environments. If the tag map
// doesn't exist then it is created.
JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->acquire_tag_map();
if (tag_map == NULL) {
MutexLocker mu(JvmtiThreadState_lock);
tag_map = ((JvmtiEnvBase*)env)->tag_map();
@ -3318,7 +3318,7 @@ void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
if (JvmtiEnv::environments_might_exist()) {
JvmtiEnvIterator it;
for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
JvmtiTagMap* tag_map = env->tag_map();
JvmtiTagMap* tag_map = env->acquire_tag_map();
if (tag_map != NULL && !tag_map->is_empty()) {
tag_map->do_weak_oops(is_alive, f);
}