[jdk17u-dev] RFR: 8268364: jmethod clearing should be done during unloading

[Kerem Kat]

On Mon, 2 Sep 2024 10:31:10 GMT, Kerem Kat <duke at openjdk.org> wrote:

> Clean backport of [8268364](https://bugs.openjdk.org/browse/JDK-8268364).
> 
> It fixes crashes when accessing jmethodIDs of a class being unloaded.
> 
> Here is the reproducer that crashes JVM in ~1 second without the patch, but works fine with it: [gist](https://gist.github.com/krk/a0800bac5bc5a01709be85637285a965).
> 
> This fix also resolves the issue reported at https://github.com/async-profiler/async-profiler/issues/974 for Java 17.
> 
> **Additional testing**: release and fastdebug with `JTREG_KEYWORDS="!headful & !external-dep & !printer"`, no new test failures with the patch.
> 
> To run the repro:
> 
> 
> javac Main.java
> gcc -shared -I"$JAVA_HOME/include" -I"$JAVA_HOME/include/linux" -fPIC repro.cpp -orepro.so
> 
> java -agentpath:"$(pwd)/repro.so" -Xmx100m Main

* JDK-8339725 is tangential but independent - either PR does not need the other.
* JDK-8267879 already in JDK 17.
* JDK-8268088 is comment only.

and others do not have patches.

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PR Comment: https://git.openjdk.org/jdk17u-dev/pull/2839#issuecomment-2353309122