RFR: 8346866: [ASAN] memoryReserver.cpp reported applying non-zero offset to non-null pointer produced null pointer [v7]

[Stefan Karlsson]

On Tue, 7 Jan 2025 11:57:07 GMT, SendaoYan <syan at openjdk.org> wrote:

>> Hi all,
>> This PR add an extra loop condition check `p2u(attach_point) > stepsize` in function `HeapReserver::Instance::try_reserve_range` to make sure the loop will not wrap around, and make UndefinedBehaviorSanitizer silent. The change do not change the original logic, risk is low.
>> 
>> Additional testing:
>> 
>> - [x]  jtreg tests(include tier1/2/3 etc., which include tests added by [PR22712](https://github.com/openjdk/jdk/pull/22712)) on linux-x64 with release build
>> - [x]  jtreg tests(include tier1/2/3 etc., which include tests added by [PR22712](https://github.com/openjdk/jdk/pull/22712)) on linux-x64 with fastdebug build
>> - [x]  jtreg tests(include tier1/2/3 etc., which include tests added by [PR22712](https://github.com/openjdk/jdk/pull/22712)) on linux-aarch64 with release build
>> - [x]  jtreg tests(include tier1/2/3 etc., which include tests added by [PR22712](https://github.com/openjdk/jdk/pull/22712)) on linux-aarch64 with fastdebug build
>
> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use explicitness of the pointer-based iteration and remove unnecessary comment

The last couple of changes made the code much more non-obvious to me.

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PR Comment: https://git.openjdk.org/jdk/pull/22897#issuecomment-2575152359