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7122253: Instrumentation.retransformClasses() leaks class bytes

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Change ClassFileParser::parseClassFile() to use the instanceKlass:_cached_class_file_bytes field to avoid leaking the cache.

Reviewed-by: coleenp, acorn, poonam
This commit is contained in:
Daniel D. Daugherty 2011-12-22 12:50:42 -08:00
parent 5232221c68
commit c210a09fdf
4 changed files with 41 additions and 9 deletions
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22
hotspot/src/share/vm/classfile/classFileParser.cpp
View File

@ -45,6 +45,7 @@
#include "oops/methodOop.hpp"
#include "oops/symbol.hpp"
#include "prims/jvmtiExport.hpp"
#include "prims/jvmtiThreadState.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/perfData.hpp"
#include "runtime/reflection.hpp"
@ -2639,8 +2640,11 @@ instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
TempNewSymbol& parsed_name,
bool verify,
TRAPS) {
// So that JVMTI can cache class file in the state before retransformable agents
// have modified it
// When a retransformable agent is attached, JVMTI caches the
// class bytes that existed before the first retransformation.
// If RedefineClasses() was used before the retransformable
// agent attached, then the cached class bytes may not be the
// original class bytes.
unsigned char *cached_class_file_bytes = NULL;
jint cached_class_file_length;
@ -2660,6 +2664,20 @@ instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
_max_bootstrap_specifier_index = -1;
if (JvmtiExport::should_post_class_file_load_hook()) {
// Get the cached class file bytes (if any) from the
// class that is being redefined.
JvmtiThreadState *state = JvmtiThreadState::state_for(jt);
KlassHandle *h_class_being_redefined =
state->get_class_being_redefined();
if (h_class_being_redefined != NULL) {
instanceKlassHandle ikh_class_being_redefined =
instanceKlassHandle(THREAD, (*h_class_being_redefined)());
cached_class_file_bytes =
ikh_class_being_redefined->get_cached_class_file_bytes();
cached_class_file_length =
ikh_class_being_redefined->get_cached_class_file_len();
}
unsigned char* ptr = cfs->buffer();
unsigned char* end_ptr = cfs->buffer() + cfs->length();

5
hotspot/src/share/vm/prims/jvmtiEnv.cpp
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@ -267,7 +267,10 @@ JvmtiEnv::RetransformClasses(jint class_count, const jclass* classes) {
instanceKlassHandle ikh(current_thread, k_oop);
if (ikh->get_cached_class_file_bytes() == NULL) {
// not cached, we need to reconstitute the class file from VM representation
// Not cached, we need to reconstitute the class file from the
// VM representation. We don't attach the reconstituted class
// bytes to the instanceKlass here because they have not been
// validated and we're not at a safepoint.
constantPoolHandle constants(current_thread, ikh->constants());
ObjectLocker ol(constants, current_thread); // lock constant pool while we query it

2
hotspot/src/share/vm/prims/jvmtiExport.cpp
View File

@ -538,8 +538,6 @@ class JvmtiClassFileLoadHookPoster : public StackObj {
_curr_env = NULL;
_cached_length_ptr = cached_length_ptr;
_cached_data_ptr = cached_data_ptr;
*_cached_length_ptr = 0;
*_cached_data_ptr = NULL;
_state = _thread->jvmti_thread_state();
if (_state != NULL) {

21
hotspot/src/share/vm/prims/jvmtiRedefineClasses.cpp
View File

@ -854,8 +854,9 @@ jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
RC_TRACE_WITH_THREAD(0x00000001, THREAD,
("loading name=%s (avail_mem=" UINT64_FORMAT "K)",
the_class->external_name(), os::available_memory() >> 10));
("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
the_class->external_name(), _class_load_kind,
os::available_memory() >> 10));
ClassFileStream st((u1*) _class_defs[i].class_bytes,
_class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
@ -3205,8 +3206,20 @@ void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
// with them was cached on the scratch class, move to the_class.
// Note: we still want to do this if nothing needed caching since it
// should get cleared in the_class too.
the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(),
scratch_class->get_cached_class_file_len());
if (the_class->get_cached_class_file_bytes() == 0) {
// the_class doesn't have a cache yet so copy it
the_class->set_cached_class_file(
scratch_class->get_cached_class_file_bytes(),
scratch_class->get_cached_class_file_len());
}
#ifndef PRODUCT
else {
assert(the_class->get_cached_class_file_bytes() ==
scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
assert(the_class->get_cached_class_file_len() ==
scratch_class->get_cached_class_file_len(), "cache lens must match");
}
#endif
// Replace inner_classes
typeArrayOop old_inner_classes = the_class->inner_classes();