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8373366: HandshakeState should disallow suspend ops for disabler threads #28740

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8373366: HandshakeState should disallow suspend ops for disabler threads #28740

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8c25f69
8373366: HandshakeState should disallow suspend ops for disabler threads
sspitsyn Dec 10, 2025
b51267f
review: restored the assert and fixed the issue caused it to fire
sspitsyn Dec 12, 2025
2b088a6
Merge
sspitsyn Dec 16, 2025
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2 changes: 1 addition & 1 deletion src/hotspot/share/runtime/handshake.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -521,7 +521,7 @@ HandshakeOperation* HandshakeState::get_op_for_self(bool allow_suspend, bool che
assert(_lock.owned_by_self(), "Lock must be held");
assert(allow_suspend || !check_async_exception, "invalid case");
#if INCLUDE_JVMTI
if (allow_suspend && _handshakee->is_disable_suspend()) {
if (allow_suspend && (_handshakee->is_disable_suspend() || _handshakee->is_vthread_transition_disabler())) {
// filter out suspend operations while JavaThread is in disable_suspend mode
allow_suspend = false;
}
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4 changes: 2 additions & 2 deletions src/hotspot/share/runtime/javaThread.cpp
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Expand Up @@ -499,7 +499,7 @@ JavaThread::JavaThread(MemTag mem_tag) :
_suspend_resume_manager(this, &_handshake._lock),

_is_in_vthread_transition(false),
DEBUG_ONLY(_is_vthread_transition_disabler(false) COMMA)
_is_vthread_transition_disabler(false),
DEBUG_ONLY(_is_disabler_at_start(false) COMMA)

_popframe_preserved_args(nullptr),
Expand Down Expand Up @@ -1161,11 +1161,11 @@ void JavaThread::set_is_in_vthread_transition(bool val) {
AtomicAccess::store(&_is_in_vthread_transition, val);
}

#ifdef ASSERT
void JavaThread::set_is_vthread_transition_disabler(bool val) {
_is_vthread_transition_disabler = val;
}

#ifdef ASSERT
void JavaThread::set_is_disabler_at_start(bool val) {
_is_disabler_at_start = val;
}
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4 changes: 2 additions & 2 deletions src/hotspot/share/runtime/javaThread.hpp
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Expand Up @@ -734,14 +734,14 @@ class JavaThread: public Thread {

private:
bool _is_in_vthread_transition; // thread is in virtual thread mount state transition
DEBUG_ONLY(bool _is_vthread_transition_disabler;) // thread currently disabled vthread transitions
bool _is_vthread_transition_disabler; // thread currently disabled vthread transitions
DEBUG_ONLY(bool _is_disabler_at_start;) // thread at process of disabling vthread transitions
public:
bool is_in_vthread_transition() const;
void set_is_in_vthread_transition(bool val);
#ifdef ASSERT
bool is_vthread_transition_disabler() const { return _is_vthread_transition_disabler; }
void set_is_vthread_transition_disabler(bool val);
#ifdef ASSERT
bool is_disabler_at_start() const { return _is_disabler_at_start; }
void set_is_disabler_at_start(bool val);
#endif
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10 changes: 5 additions & 5 deletions src/hotspot/share/runtime/mountUnmountDisabler.cpp
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Expand Up @@ -286,13 +286,13 @@ MountUnmountDisabler::disable_transition_for_one() {
// carrierThread to float up.
// This pairs with the release barrier in end_transition().
OrderAccess::acquire();
DEBUG_ONLY(JavaThread::current()->set_is_vthread_transition_disabler(true);)
JavaThread::current()->set_is_vthread_transition_disabler(true);
}

// disable transitions for all virtual threads
void
MountUnmountDisabler::disable_transition_for_all() {
DEBUG_ONLY(JavaThread* thread = JavaThread::current();)
JavaThread* thread = JavaThread::current();
DEBUG_ONLY(thread->set_is_disabler_at_start(true);)

MonitorLocker ml(VThreadTransition_lock);
Expand Down Expand Up @@ -327,7 +327,7 @@ MountUnmountDisabler::disable_transition_for_all() {
// carrierThread to float up.
// This pairs with the release barrier in end_transition().
OrderAccess::acquire();
DEBUG_ONLY(thread->set_is_vthread_transition_disabler(true);)
thread->set_is_vthread_transition_disabler(true);
DEBUG_ONLY(thread->set_is_disabler_at_start(false);)
}

Expand All @@ -350,7 +350,7 @@ MountUnmountDisabler::enable_transition_for_one() {
if (java_lang_Thread::vthread_transition_disable_count(_vthread()) == 0) {
ml.notify_all();
}
DEBUG_ONLY(JavaThread::current()->set_is_vthread_transition_disabler(false);)
JavaThread::current()->set_is_vthread_transition_disabler(false);
}

// enable transitions for all virtual threads
Expand All @@ -376,7 +376,7 @@ MountUnmountDisabler::enable_transition_for_all() {
if (global_vthread_transition_disable_count() == base_disable_count || _is_exclusive) {
ml.notify_all();
}
DEBUG_ONLY(thread->set_is_vthread_transition_disabler(false);)
thread->set_is_vthread_transition_disabler(false);
}

int MountUnmountDisabler::global_vthread_transition_disable_count() {
Expand Down