8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state #27112

lmesnik · 2025-09-05T06:22:15Z

This is the second attempt to fix method post_meth_exit to correctly set state and preserve result.
The related fix here:
b7b64bb
Hope fix became clarere now.

There 2 problems in this post_meth_exit:

The result is preserved only if state->is_enabled(JVMTI_EVENT_METHOD_EXIT) however transition in the JRT_BLOCK_END happens always. So there is a risk of loosing method results in the interp_only mode.
The method get_jvmti_thread_state should be called when thread is in vm state only.

The fix adds post_method_exit_transition to have single exit point with oop restoration.

Progress

Change must be properly reviewed (1 review required, with at least 1 Reviewer)
Change must not contain extraneous whitespace
Commit message must refer to an issue

Issue

JDK-8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state (Bug - P4)

Reviewers

David Holmes (@dholmes-ora - Reviewer)
Martin Doerr (@TheRealMDoerr - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27112/head:pull/27112
$ git checkout pull/27112

Update a local copy of the PR:
$ git checkout pull/27112
$ git pull https://git.openjdk.org/jdk.git pull/27112/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27112

View PR using the GUI difftool:
$ git pr show -t 27112

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27112.diff

Using Webrev

Link to Webrev Comment

bridgekeeper · 2025-09-05T06:22:53Z

👋 Welcome back lmesnik! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2025-09-05T06:23:35Z

@lmesnik This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state

Reviewed-by: dholmes, mdoerr

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 43 new commits pushed to the master branch:

cfb8093: 8364103: Convert existing sprintf-chains to stringStream
e16c510: 8367231: [BACKOUT] JDK-8366363: MemBaseline accesses VMT without using lock
67bb22f: 8367085: Sort os/posix includes
... and 40 more: https://git.openjdk.org/jdk/compare/1e90af08abb74df9ec4ab94b67deeae5c1c9fee1...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

openjdk · 2025-09-05T06:24:03Z

@lmesnik The following labels will be automatically applied to this pull request:

hotspot
serviceability

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

mlbridge · 2025-09-05T06:29:31Z

Webrevs

dholmes-ora

I've taken a first pass through and the code reorg seems okay. It would have been a little clearer without factoring out the transition method.

Thanks

dholmes-ora · 2025-09-08T05:38:21Z

src/hotspot/share/prims/jvmtiExport.cpp

+  // At this point we only have the address of a "raw result" and
+  // we just call into the interpreter to convert this into a jvalue.
+  // The post_method_exit_transition always makes transition to vm and back
+  // where GC can happen. So it is needed to preserve result  and then restore it


Suggested change

// where GC can happen. So it is needed to preserve result and then restore it

// where GC can happen. So it is needed to preserve result and then restore it

src/hotspot/share/prims/jvmtiExport.cpp

TheRealMDoerr · 2025-09-08T15:36:45Z

src/hotspot/share/prims/jvmtiExport.cpp

-    }
+  BasicType type = current_frame.interpreter_frame_result(&oop_result, &value);
+  assert(type == T_VOID || current_frame.interpreter_frame_expression_stack_size() > 0,
+          "Stack shouldn't be empty");


I think this assertion needs an adaptation. The expression stack can be empty for native method calls. The result does not necessarily need to be on the expression stack depending on the platform.
Or what else is the reason it is expected to be non-empty?

Thanks for adding the native check! Looks good to me, now.

dholmes-ora

Thanks that looks clearer to me now.

One pre-existing typo.

dholmes-ora · 2025-09-09T06:57:15Z

src/hotspot/share/prims/jvmtiExport.cpp

+    }
+  JRT_BLOCK_END
+  if (interp_only) {
+    // The JRT_BLOCK_END can safepoint in ThreadInVMfromJava desctructor. Now it is safe to allow


Suggested change

// The JRT_BLOCK_END can safepoint in ThreadInVMfromJava desctructor. Now it is safe to allow

// The JRT_BLOCK_END can safepoint in ThreadInVMfromJava destructor. Now it is safe to allow

fix

a031b40

openjdk bot added serviceability serviceability-dev@openjdk.org hotspot hotspot-dev@openjdk.org rfr Pull request is ready for review labels Sep 5, 2025

comment is fixed.

c1de44f

lmesnik added 3 commits September 4, 2025 23:35

comment

77c9c7a

Merge branch 'master' of https://github.com/openjdk/jdk into 8365192-2

ea2dff0

small improvements

0bd9c98

dholmes-ora reviewed Sep 8, 2025

View reviewed changes

lmesnik added 2 commits September 8, 2025 08:28

reverted to single method.

118d39e

more changes reverted

ea941c2

TheRealMDoerr reviewed Sep 8, 2025

View reviewed changes

lmesnik added 2 commits September 8, 2025 08:56

comments fixed.

03c172a

interopnly_state should be saved

3a16979

dholmes-ora approved these changes Sep 9, 2025

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label Sep 9, 2025

TheRealMDoerr approved these changes Sep 9, 2025

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state #27112

8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state #27112

lmesnik commented Sep 5, 2025 •

edited by openjdk bot

Loading

Uh oh!

bridgekeeper bot commented Sep 5, 2025

Uh oh!

openjdk bot commented Sep 5, 2025 •

edited

Loading

Uh oh!

openjdk bot commented Sep 5, 2025

Uh oh!

mlbridge bot commented Sep 5, 2025 •

edited

Loading

Uh oh!

dholmes-ora left a comment

Uh oh!

dholmes-ora Sep 8, 2025

Uh oh!

Uh oh!

TheRealMDoerr Sep 8, 2025

Uh oh!

TheRealMDoerr Sep 8, 2025

Uh oh!

dholmes-ora left a comment

Uh oh!

dholmes-ora Sep 9, 2025

Uh oh!

Uh oh!

	// where GC can happen. So it is needed to preserve result and then restore it
	// where GC can happen. So it is needed to preserve result and then restore it

	// The JRT_BLOCK_END can safepoint in ThreadInVMfromJava desctructor. Now it is safe to allow
	// The JRT_BLOCK_END can safepoint in ThreadInVMfromJava destructor. Now it is safe to allow

8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state #27112

Are you sure you want to change the base?

8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state #27112

Conversation

lmesnik commented Sep 5, 2025 • edited by openjdk bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Progress

Issue

Reviewers

Reviewing

Uh oh!

bridgekeeper bot commented Sep 5, 2025

Uh oh!

openjdk bot commented Sep 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

openjdk bot commented Sep 5, 2025

Uh oh!

mlbridge bot commented Sep 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Webrevs

Uh oh!

dholmes-ora left a comment

Choose a reason for hiding this comment

Uh oh!

dholmes-ora Sep 8, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

TheRealMDoerr Sep 8, 2025

Choose a reason for hiding this comment

Uh oh!

TheRealMDoerr Sep 8, 2025

Choose a reason for hiding this comment

Uh oh!

dholmes-ora left a comment

Choose a reason for hiding this comment

Uh oh!

dholmes-ora Sep 9, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

lmesnik commented Sep 5, 2025 •

edited by openjdk bot

Loading

openjdk bot commented Sep 5, 2025 •

edited

Loading

mlbridge bot commented Sep 5, 2025 •

edited

Loading