On Mon, 28 Jul 2025 06:57:42 GMT, Serguei Spitsyn <[email protected]> wrote:
>> If JVMTI `StopThread` is done when the thread is in certain various states
>> (but not all states), after the `async` exception is delivered and handled,
>> hotspot leaves the thread's `interrupted` flag set. The end result is the
>> next time the thread does something like `Thread.sleep()`, it will
>> immediately get an `InterruptedException`.
>>
>> The fix is to clear the `interrupted` flag in the
>> `JavaThread::handle_async_exception()` after an `async` pending exception
>> has been set to be thrown with the `set_pending_exception()`.
>>
>> There are a couple of concerns with this fix which would be nice to sort out
>> with reviewers:
>> 1. The proposed fix may clear the interrupt state when it was already set
>> prior to the issuing of the `StopThread()` (this concern was raised by
>> @dholmes-ora in a comment of this JBS issue)
>> 2. The impacted code path is shared between the class
>> `InstallAsyncExceptionHandshakeClosure` used by the JVMTI `StopThread`
>> implementation and the class `ScopedAsyncExceptionHandshakeClosure` used by
>> the `ScopedMemoryAccess`
>>
>> I feel that clearing the `interrupted` flag byt the
>> `JavaThread::handle_async_exception()` is a right thing to do even though it
>> was set before the call to `JavaThread::install_async_exception()`. Also, it
>> has to be done for both `StopThread` and `ScopedMemoryAccess`.
>>
>> The fix also includes minor tweaks of the test `StopThreadTest` to make the
>> issue reproducible with it.
>>
>> Testing:
>> - Mach5 tiers 1-6 are passed
>> - Ran the updated reproducer test
>> `hotspot/jtreg/serviceability/jvmti/vthread/StopThreadTest`
>
> Serguei Spitsyn has updated the pull request incrementally with one
> additional commit since the last revision:
>
> review: implemented a suggestion: do not set interrupt flag at all
I've implemented and pushed the suggestion from Patricio. The mach5 tiers 1-6
are clean.
I'm not sure about correctness of the tweak in the `JavaThread::sleep_nanos()`:
@@ -2122,6 +2117,9 @@ bool JavaThread::sleep_nanos(jlong nanos) {
jlong nanos_remaining = nanos;
for (;;) {
+ if (has_async_exception_condition()) {
+ return false;
+ }
// interruption has precedence over timing out
if (this->is_interrupted(true)) {
return false;
The mach5 tiers 1-6 tests are all passed without this tweak.
-------------
PR Comment: https://git.openjdk.org/jdk/pull/26365#issuecomment-3125809023
