RFR: 8340631: assert(reserved_rgn->contain_region(base_addr, size)) failed: Reserved CDS region should contain this mapping region [v4]

[Stefan Karlsson]

On Wed, 18 Dec 2024 21:37:53 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> What testing with `UseCompressedClassPointers` set to false, this assert is hit due to memory being released twice during the failure path of CDS archive mapping. This patch makes it so the RW and RO regions are only released once at the end in `MetaspaceShared::release_reserved_spaces()`. 
>> 
>> This patch hides `unmap_region` as the method should not be called on regions that were reserved. Instead, the region is skipped and we verify that it is indeed in the reserved space. Verified` with tier 1-4 tests.
>
> Matias Saavedra Silva has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added assert and made unmap_region private

src/hotspot/share/cds/filemap.cpp line 2424:

> 2422:       size_t size = r->used_aligned();
> 2423: 
> 2424:       assert(rs.is_reserved(), "must be");

This is already checked in the if-statement.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22743#discussion_r1891407540