[jdk17u-dev] RFR: 8278627: Shenandoah: TestHeapDump test failed

[Aleksey Shipilev]

On Tue, 4 Jan 2022 19:56:31 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> I would like to backport this patch to 17u, it fixes a potential fatal crash during heap dump.
> 
> The original patch does not apply cleanly, due to context differences, e.g. JDK-8277342 and JDK-8268368 do not in 17u.
> 
> Test:
> - [x] hotspot_gc_shenandoah

src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.cpp line 282:

> 280: void ShenandoahHeapIterationRootScanner::roots_do(OopClosure* oops) {
> 281:   // Must use _claim_other to avoid interfering with concurrent CLDG iteration
> 282:   CLDToOopClosure clds(oops, ClassLoaderData::_claim_other);

I am confused a bit. The original code for 17u has `ClassLoaderData::_claim_none` here, the backport changes it to `_claim_other`. The JDK 18 had `_claim_other` both in original code and in the patch. What is going on here?

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PR: https://git.openjdk.java.net/jdk17u-dev/pull/58