RFR: 8369393: NMT: poison the canaries of malloc header under ASAN build [v11]

[Afshin Zafari]

On Wed, 15 Oct 2025 07:31:58 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

>> NMT can detect malloc'd memory corruption using canary tests at header and footer of every memory region. This can only be done at free time of the memory where NNT checks the canaries and report error if they are not as expected.
>> In this PR, the canary parts also are poisoned using ASAN API to get notified whenever a read/write op is done. on the canary parts. `_size` member of the malloc header is also poisoned, since it is used for finding the footer address.
>
> Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:
> 
>   another NOT_LP64

I prefer to put the APH in `sanitizers/address.hpp`. What do you think?

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PR Comment: https://git.openjdk.org/jdk/pull/27685#issuecomment-3405645829