[jdk17u-dev] RFR: 8274753: ZGC: SEGV in MetaspaceShared::link_shared_classes

[Goetz Lindenmaier]

On Tue, 25 Jan 2022 09:20:30 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Hi all,
> 
> not a clean backport. I had to fix up classLoaderData.cpp a bit because `SystemDictionaryShared::handle_class_unloading(ik);` does not yet exist in jdk17 and I did not want to bring the dependent cleanup change into jdk17 too (among other things because Oracle seems not to have done it either in their closed backport as far as I can glean from the JBS tags).
> 
> Tested in SAP nightlies for about a week now.
> 
> Thanks!

Marked as reviewed by goetz (Reviewer).

src/hotspot/share/classfile/classLoaderData.cpp line 893:

> 891:       if (Arguments::is_dumping_archive()) {
> 892:         SystemDictionaryShared::remove_dumptime_info(ik);
> 893:       }

This is a part of handle_class_unloading(). I.e., you basically "undo" '8267189: Remove duplicated unregistered classes from dynamic archive'. That change replaced remove_dumptime_info() by handle_class_unloading() which calls remove_dumptime_info().
And you add the check for is_dumping_archive() that was 
added to handle_class_unloading() in 
'8265602: -XX:DumpLoadedClassList should support custom loaders'.

LGTM

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PR: https://git.openjdk.java.net/jdk17u-dev/pull/118