On Fri, 16 Jan 2026 08:00:01 GMT, Serguei Spitsyn <[email protected]> wrote:
>> An asynchronous handshake operation (`ThreadSelfSuspensionHandshakeClosure`) >> can be installed when the target thread is not in a `MountUnmountDisabler` >> scope. But the target thread can enter such scope by the time the operation >> is self-processed by the target thread. >> >> This is fixed by a small tweak in the function >> `HandshakeOperation* HandshakeState::get_op_for_self(bool allow_suspend, >> bool check_async_exception)`. >> The tweak is to skip a `HandshakeOperation` if >> `_handshakee->is_vthread_transition_disabler() == true`, so the same >> temporary suspension disabling mechanism would be used as for >> `_handshakee->is_disable_suspend() == true`. >> >> All other changes are to move the `is_vthread_transition_disabler()` out of >> DEBUG to product. >> >> Testing: >> - In progress: mach5 tiers 1-6 > > Serguei Spitsyn has updated the pull request incrementally with one > additional commit since the last revision: > > 8375362: deadlock with unmount of suspended virtual thread interrupting > another virtual thread I've added the following fix for [JDK-8375362](https://bugs.openjdk.org/browse/JDK-8375362) as we agreed with Patricio: @@ -129,7 +129,8 @@ bool MountUnmountDisabler::is_start_transition_disabled(JavaThread* thread, oop int base_disable_count = notify_jvmti_events() ? 1 : 0; return java_lang_Thread::vthread_transition_disable_count(vthread) > 0 || global_vthread_transition_disable_count() > base_disable_count JVMTI_ONLY(|| (JvmtiVTSuspender::is_vthread_suspended(java_lang_Thread::thread_id(vthread)) || thread->is_suspended())); JVMTI_ONLY(|| (!thread->is_vthread_transition_disabler() && (JvmtiVTSuspender::is_vthread_suspended(java_lang_Thread::thread_id(vthread)) || thread->is_suspended()))); } void MountUnmountDisabler::start_transition(JavaThread* current, oop vthread, bool is_mount, bool is_thread_end) { ------------- PR Comment: https://git.openjdk.org/jdk/pull/28740#issuecomment-3762080269
