RFR: 8366787: Test runtime/StackGuardPages/TestStackGuardPagesNative.java hangs on some platforms [v2]

[David Holmes]

On Wed, 10 Sep 2025 02:52:51 GMT, mazhen <duke at openjdk.org> wrote:

>> #### Summary
>> 
>> This PR fixes a hang in the `TestStackGuardPagesNative.java` test that occurs on certain Linux distributions (e.g., CentOS 7). The fix replaces an unbounded `for(;;)` loop in the native test code (`exeinvoke.c`) with a bounded `while` loop, making the test's behavior deterministic and robust across all platforms.
>> 
>> #### Problem
>> 
>> The test would hang and eventually time out on some platforms. This was caused by an unbounded `for(;;)` loop in the `do_overflow` function, which was introduced as part of the "hardening" fix in `JDK-8295344`.
>> 
>> *   On platforms like **CentOS 7**, this unbounded loop would not encounter a terminating signal in a timely manner, causing the native process to hang indefinitely until killed by the test harness.
>> *   In contrast, on platforms like **Ubuntu 24**, the test would coincidentally pass because a `SEGV_MAPERR` would happen to terminate the loop. This highlighted that the test's success was reliant on platform-specific side effects, masking the underlying issue.
>> 
>> #### Solution
>> 
>> The solution is to replace the unbounded `for(;;)` loop with a bounded `while` loop. The condition `while (_kp_rec_count == 0 || _rec_count < _kp_rec_count)` ensures that the loop terminates deterministically after a specific number of allocations, corresponding to the overflow depth detected in the test's first phase.
>> 
>> This change makes the test's logic robust and its behavior consistent across different environments.
>
> mazhen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Restore TestStackGuardPagesNative to ProblemList as requested

Looks good. Thanks

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27114#pullrequestreview-3204733003