RFR: 8342303: Segfault in update_inherited_vtable: AppCDS, old bytecode, and redefineClasses

[David Holmes]

On Wed, 23 Oct 2024 17:15:53 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

> A simple fix to avoid referencing invalid vtable and itable entires in `InstanceKlass::restore_unshareable_info` if a class is not linked during CDS dump time.
> 
> Passed tiers 1 - 4 testing.
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Functional fix looks good. Unclear about the the test details ...

Thanks

test/hotspot/jtreg/runtime/cds/appcds/jvmti/redefineClasses/OldClassAndRedefineClassApp.java line 34:

> 32:         System.out.println("Main: loading OldSuper");
> 33:         // Load an old class (version 49), but not linking it.
> 34:         Thread.currentThread().getContextClassLoader().loadClass("OldSuper");

Why the context classloader? Has it been set in this test?

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PR Review: https://git.openjdk.org/jdk/pull/21667#pullrequestreview-2401349691
PR Review Comment: https://git.openjdk.org/jdk/pull/21667#discussion_r1820479420