RFR: 8373025: Test: test/hotspot/jtreg/gc/cslocker/TestCSLocker.java may deadlock

[Albert Mingkun Yang]

On Wed, 3 Dec 2025 15:10:58 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

> The main threads call to `csLocker.unlock();` may cause an allocation which may trigger a GC. This can lead to a deadlock because we have a native thread which is waiting on a signal from the main thread (which is sent in `csLocker.unlock()`) to `ReleasePrimitiveArrayCritical`. Without the call to ReleasePrimitiveArrayCritical the some GCs may be blocked.
> 
> I suggest we remove the dependency on a java thread for the `GetPrimitiveArrayCritical` / `ReleasePrimitiveArrayCritical` pair. And simply do the lock and the sleep inside native.
> 
> * Testing
>   * Stress testing test/hotspot/jtreg/gc/cslocker/TestCSLocker.java with both SerialGC and ZGC and small heap sizes
>   * GHA

test/hotspot/jtreg/gc/cslocker/TestCSLocker.java line 41:

> 39: public class TestCSLocker extends Thread
> 40: {
> 41:     static int timeoutMillis = 5000;

Seems unused now.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28638#discussion_r2585663274