RFR: 8360048: NMT crash in gtest/NMTGtests.java: fatal error: NMT corruption: Block at 0x0000017748307120: header canary broken [v2]

[David Holmes]

> This is a clone of https://github.com/openjdk/jdk/pull/25950 that we need to get integrated ASAP.
> 
> ---
> 
> 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.
> 
> ---
> 
> I'm re-testing with tiers 1-4

David Holmes has updated the pull request incrementally with two additional commits since the last revision:

 - Update test/hotspot/gtest/runtime/test_virtualMemoryTracker.cpp
   
   Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
 - Update src/hotspot/share/nmt/virtualMemoryTracker.cpp
   
   Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/26284/files
  - new: https://git.openjdk.org/jdk/pull/26284/files/a07a5c1b..faa38c29

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26284&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26284&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26284.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26284/head:pull/26284

PR: https://git.openjdk.org/jdk/pull/26284