Memory Corruption in JDK-21 on x86_64 with AVX-512

[Viswanathan, Sandhya]

Copying Tobias. 

From what I see JDK21 update schedule has a mid-October release plan (https://wiki.openjdk.org/display/JDKUpdates/JDK+21u).

Tobias, do you know the code freeze date for that. Hopefully, we still have a couple of days left.

At the minimum we should revert to return nullptr in both LoadVectorMaskedNode::Ideal and StoreVectorMaskedNode::Ideal as a workaround.

Best Regards,
Sandhya

-----Original Message-----
From: hotspot-compiler-dev <hotspot-compiler-dev-retn at openjdk.org> On Behalf Of Carter Kozak
Sent: Wednesday, September 27, 2023 7:26 AM
To: Xiaohong Gong <Xiaohong.Gong at arm.com>; hotspot-compiler-dev at openjdk.org
Subject: Re: Memory Corruption in JDK-21 on x86_64 with AVX-512

Thank you for such a quick diagnosis, I really appreciate it!

While I don't have a good sense of the mapping between bug severity and backport/release criteria, I suspect this issue may be a strong candidate for an out-of-band jdk-21 release. I'm certainly biased because I had invalid bytes silently persisted, and defer to folks closer to the process.

Best,
Carter Kozak

On Wed, Sep 27, 2023, at 02:57, Xiaohong Gong wrote:
> Hi Carter,
>  
> Thanks for reporting this issue!
>  
> It seems the issue is caused by the calling of the super class’s “Ideal()” method in “LoadVectorMaskedNode::Ideal()” (code is: 8286941: Add mask IR for partial vector operations for ARM SVE by XiaohongGong · Pull Request #9037 · openjdk/jdk (github.com) <https://github.com/openjdk/jdk/pull/9037/files#diff-692826251cae892bc4737919579c6afbd317551cd507f99c7bd29d585c1282e2R1028>).
> Some optimization applied on “LoadNode” is not suitable for “LoadVectorMaskedNode” now. Reverting it back to “return nullptr” can make your benchmark pass.
>  
> I will look at this issue and try to fix it next. Thanks!