RFR: 8357601: Checked version of JNI Release<type>ArrayElements needs to filter out known wrapped arrays

[David Holmes]

On Tue, 1 Jul 2025 12:31:04 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> The checked version of `Get`/`Release<type>ArrayElements` uses `GuardedMemory` to perform error checking. When releasing the array the code needs to check for the known array tags from the other JNI APIs and report an error.
>> 
>> We also expand `GuardedMemory` to allow for a second tag word so that we can discriminate additional allocation sites i.e. identifying use of `Get`/`SetPrimitiveArrayCritical`. And add further robustness to guard verification by using `SafeFetch`.
>> 
>> Testing
>>  - new test
>>  - Tiers 1-4 (sanity)
>
> Cool test. Looks fine.  I had some earlier comments but nothing that would really improve the change.

Thanks for the review @coleenp !

> src/hotspot/share/prims/jniCheck.cpp line 400:
> 
>> 398:   if (orig_result == STRING_TAG || orig_result == STRING_UTF_TAG) {
>> 399:     bool was_utf = orig_result == STRING_UTF_TAG;
>> 400:     tty->print_cr("%s: called on something allocated by %s",
> 
> Can you use log_warning(memory) for this message rather than tty?
> Maybe these should be tty since they're in jniCheck.

`tty` is used throughout the jniCheck code.

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PR Comment: https://git.openjdk.org/jdk/pull/25444#issuecomment-3026627820
PR Review Comment: https://git.openjdk.org/jdk/pull/25444#discussion_r2179232621