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8255452: Doing GC during JVMTI MethodExit event posting breaks return oop

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Reviewed-by: coleenp, dlong, rrich, sspitsyn
This commit is contained in:
Erik Österlund 2020-11-05 16:17:33 +00:00
parent ba2ff3a6d2
commit 3a02578b33
3 changed files with 46 additions and 16 deletions
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5
src/hotspot/share/interpreter/interpreterRuntime.cpp
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@ -1269,7 +1269,10 @@ JRT_ENTRY(void, InterpreterRuntime::post_method_entry(JavaThread *thread))
JRT_END
JRT_ENTRY(void, InterpreterRuntime::post_method_exit(JavaThread *thread))
// This is a JRT_BLOCK_ENTRY because we have to stash away the return oop
// before transitioning to VM, and restore it after transitioning back
// to Java. The return oop at the top-of-stack, is not walked by the GC.
JRT_BLOCK_ENTRY(void, InterpreterRuntime::post_method_exit(JavaThread *thread))
LastFrameAccessor last_frame(thread);
JvmtiExport::post_method_exit(thread, last_frame.method(), last_frame.get_frame());
JRT_END

44
src/hotspot/share/prims/jvmtiExport.cpp
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@ -1564,12 +1564,8 @@ void JvmtiExport::post_method_exit(JavaThread *thread, Method* method, frame cur
HandleMark hm(thread);
methodHandle mh(thread, method);
EVT_TRIG_TRACE(JVMTI_EVENT_METHOD_EXIT, ("[%s] Trg Method Exit triggered %s.%s",
JvmtiTrace::safe_get_thread_name(thread),
(mh() == NULL) ? "NULL" : mh()->klass_name()->as_C_string(),
(mh() == NULL) ? "NULL" : mh()->name()->as_C_string() ));
JvmtiThreadState *state = thread->jvmti_thread_state();
if (state == NULL || !state->is_interp_only_mode()) {
// for any thread that actually wants method exit, interp_only_mode is set
return;
@ -1578,13 +1574,11 @@ void JvmtiExport::post_method_exit(JavaThread *thread, Method* method, frame cur
// return a flag when a method terminates by throwing an exception
// i.e. if an exception is thrown and it's not caught by the current method
bool exception_exit = state->is_exception_detected() && !state->is_exception_caught();
if (state->is_enabled(JVMTI_EVENT_METHOD_EXIT)) {
Handle result;
jvalue value;
value.j = 0L;
if (state->is_enabled(JVMTI_EVENT_METHOD_EXIT)) {
// if the method hasn't been popped because of an exception then we populate
// the return_value parameter for the callback. At this point we only have
// the address of a "raw result" and we just call into the interpreter to
@ -1594,9 +1588,36 @@ void JvmtiExport::post_method_exit(JavaThread *thread, Method* method, frame cur
BasicType type = current_frame.interpreter_frame_result(&oop_result, &value);
if (is_reference_type(type)) {
result = Handle(thread, oop_result);
value.l = JNIHandles::make_local(thread, result());
}
}
}
// Deferred transition to VM, so we can stash away the return oop before GC
// Note that this transition is not needed when throwing an exception, because
// there is no oop to retain.
JRT_BLOCK
post_method_exit_inner(thread, mh, state, exception_exit, current_frame, value);
JRT_BLOCK_END
if (result.not_null() && !mh->is_native()) {
// We have to restore the oop on the stack for interpreter frames
*(oop*)current_frame.interpreter_frame_tos_address() = result();
}
}
void JvmtiExport::post_method_exit_inner(JavaThread* thread,
methodHandle& mh,
JvmtiThreadState *state,
bool exception_exit,
frame current_frame,
jvalue& value) {
EVT_TRIG_TRACE(JVMTI_EVENT_METHOD_EXIT, ("[%s] Trg Method Exit triggered %s.%s",
JvmtiTrace::safe_get_thread_name(thread),
(mh() == NULL) ? "NULL" : mh()->klass_name()->as_C_string(),
(mh() == NULL) ? "NULL" : mh()->name()->as_C_string() ));
if (state->is_enabled(JVMTI_EVENT_METHOD_EXIT)) {
JvmtiEnvThreadStateIterator it(state);
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
if (ets->is_enabled(JVMTI_EVENT_METHOD_EXIT)) {
@ -1607,9 +1628,6 @@ void JvmtiExport::post_method_exit(JavaThread *thread, Method* method, frame cur
JvmtiEnv *env = ets->get_env();
JvmtiMethodEventMark jem(thread, mh);
if (result.not_null()) {
value.l = JNIHandles::make_local(thread, result());
}
JvmtiJavaThreadEventTransition jet(thread);
jvmtiEventMethodExit callback = env->callbacks()->MethodExit;
if (callback != NULL) {
@ -1801,7 +1819,9 @@ void JvmtiExport::notice_unwind_due_to_exception(JavaThread *thread, Method* met
if(state->is_interp_only_mode()) {
// method exit and frame pop events are posted only in interp mode.
// When these events are enabled code should be in running in interp mode.
JvmtiExport::post_method_exit(thread, method, thread->last_frame());
jvalue no_value;
no_value.j = 0L;
JvmtiExport::post_method_exit_inner(thread, mh, state, true, thread->last_frame(), no_value);
// The cached cur_stack_depth might have changed from the
// operations of frame pop or method exit. We are not 100% sure
// the cached cur_stack_depth is still valid depth so invalidate

7
src/hotspot/share/prims/jvmtiExport.hpp
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@ -193,6 +193,13 @@ class JvmtiExport : public AllStatic {
// dependency information is complete or not.
static bool _all_dependencies_are_recorded;
static void post_method_exit_inner(JavaThread* thread,
methodHandle& mh,
JvmtiThreadState *state,
bool exception_exit,
frame current_frame,
jvalue& value);
public:
inline static bool has_redefined_a_class() {
JVMTI_ONLY(return _redefinition_count != 0);