RFR: 8369393: NMT: poison the malloc header and footer under ASAN build [v2]

[Paul Hübner]

On Wed, 3 Dec 2025 14:43:45 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

>> src/hotspot/share/nmt/mallocHeader.inline.hpp line 170:
>> 
>>> 168:   ASAN_UNPOISON_MEMORY_REGION(header->footer_address(), footer_size);
>>> 169:   resolve_checked(memblock);
>>> 170:   header->mark_block_as_dead();
>> 
>> Unrelated to this PR: is there a reason we `mark_block_as_dead()` but `revive()` as opposed to `mark_block_as_revived()`?
>
> I prefer `mark_block_as_alive()` with no assertion on being already `dead`. `revive()` with assertion that it has to be `dead` already. Thoughts?

Works for me. But I see no assertion in the current code that asserts it has to be dead.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28503#discussion_r2585410681