RFR: 8378194: Protect process_pending_interp_only() work with JvmtiThreadState_lock

[Serguei Spitsyn]

On Fri, 20 Feb 2026 22:58:37 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> The function `JvmtiThreadState::process_pending_interp_only()` should protect the check with `state->is_pending_interp_only_mode()` and call to `JvmtiEventController::enter_interp_only_mode(state)` with the `JvmtiThreadState_lock`. Some level of optimization with a check of `seen_interp_only_mode()` is used as the code path of the `process_pending_interp_only()` is hot. Then the `seen_interp_only_mode()` has to be set somewhat earlier when the `is_pending_interp_only_mode()` is set.
>> This issue was discovered when in the work on the PR update of https://bugs.openjdk.org/browse/JDK-8373367 .
>> 
>> Testing:
>>  - TBD: mach5 tiers 1-5
>
> src/hotspot/share/prims/jvmtiThreadState.inline.hpp line 175:
> 
>> 173:       assert(state->get_thread() == current, "sanity check");
>> 174:       assert(!state->is_interp_only_mode(), "sanity check");
>> 175:       JvmtiEventController::enter_interp_only_mode(state);
> 
> I think it makes sense to add `assert(JvmtiThreadState_lock->is_locked()` in `JvmtiEventController::enter_interp_only_mode` to avoid similar issues in the future

Good suggestion, thanks. Addressed now. Added assert to both `JvmtiThreadState::enter_interp_only_mode()` and `JvmtiThreadState::leave_interp_only_mode()`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29800#discussion_r2835976881