RFR: 8271925: ZGC: Arraycopy stub passes invalid oop to load barrier

Thu Aug 5 08:22:41 UTC 2021

On Thu, 5 Aug 2021 08:08:47 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

> The fix for [JDK-8270461](https://bugs.openjdk.java.net/browse/JDK-8270461), see [PR 252](https://git.openjdk.java.net/jdk17/pull/252), made sure that the arraycopy offset when cloning an oop array always points to the first element of the array. However, it missed to adjust the copy length as well, leading to reading/copying 8 bytes beyond the end of the array.
> 
> This only reproduces in Valhalla (probably because the mark word layout differs there) and only with  `-XX:-UseCompressedClassPointers`. I'll backport the fix to JDK 17u.
> 
> Thanks,
> Tobias

Thanks for the review, Nils!

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PR: https://git.openjdk.java.net/jdk/pull/5014