RFR: 8274944: AppCDS dump causes SEGV in VM thread while adjusting lambda proxy class info

Yumin Qi minqi at openjdk.java.net
Fri Oct 22 17:06:08 UTC 2021

On Thu, 21 Oct 2021 21:42:45 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

> During dumping of CDS archive, the `ArchiveBuilder::gather_klass_and_symbol` set the address of an object to null if the
> object cannot be archived. Since the lambda proxy class in this scenario contains an old version (major version < 50) of
> interface which has been linked, the class won't be archived and its address will be set to null. The `SystemDictionaryShared::adjust_lambda_proxy_class_dictionary` is called after 
> `ArchiveBuilder::gather_klass_and_symbol` and thus encountered the null pointer.
> A fix is to add a function `SystemDictionaryShared::cleanup_lambda_proxy_class_dictionary` to cleanup the
> `_dumptime_lambda_proxy_class_dictionary` at the beginning of the CDS dumping operation.
> The proposed fix passed tiers 1 - 4 testing (including the new tests).


src/hotspot/share/classfile/systemDictionaryShared.cpp line 1603:

> 1601: class CleanupDumpTimeLambdaProxyClassTable: StackObj {
> 1602:  public:
> 1603:   CleanupDumpTimeLambdaProxyClassTable() {}

Why need a explicit public constructor for nothing?


Marked as reviewed by minqi (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6070

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