RFR: 8360048: NMT crash in gtest/NMTGtests.java: fatal error: NMT corruption: Block at 0x0000017748307120: header canary broken

[Johan Sjölen]

On Tue, 24 Jun 2025 07:52:38 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

> The canary header test failed since there were concurrent `remove` and `free()` from the tree. The `remove` operations are synch'ed with corresponding NMT lock. The `ReserveMemory::reserve()` uses the same lock internally and is not included in the locked code block.
> 
> Tests: tier5 {macosx-aarch64, linux-x64, windows-x64} x {debug, release}

It would be good if we could remove the dependency on the global instance in the source code and create new VMT's for each test. That would make the tests less brittle.

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Marked as reviewed by jsjolen (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25950#pullrequestreview-2952858818