RFR: 8260930: AARCH64: Invalid value passed to critical JNI function

[Yangfei (Felix)]

Hi,

Thanks for the reply.

> -----Original Message-----
> From: jdk8u-dev [mailto:jdk8u-dev-retn at openjdk.java.net] On Behalf Of
> Andrew Haley
> Sent: Wednesday, February 3, 2021 5:45 PM
> To: jdk8u-dev at openjdk.java.net
> Subject: Re: RFR: 8260930: AARCH64: Invalid value passed to critical JNI
> function
> 
> On 2/3/21 6:31 AM, Yangfei (Felix) wrote:
> >     I think we should also fix this for 8u aarch64.
> 
> Why? It doesn't affect any user's code.

Well, I was assuming this is a "significant" bug according to the following guideline on [1]:

" All fixes that significantly improve stability, security or performance and do not change behavioural compatibility [1]will be considered for jdk8u. To use the language of the JDK 6 project, by default such fixes are assumed to be applicable to jdk8u, especially if having "soaked" in later JDK releases for a time without incident. By "significant" I mean any bug that affects runtime behaviour in a way that either produces incorrect results, poor performance, or crashes the VM, especially TCK failures. Failures that are due solely to bizarre or unreasonable combinations of -XX: command-line parameters probably don't reach the bar of significance, and fixing them will carry a non-zero risk of breaking something, so we should err on the size of caution. For now it's mostly "bug fixes only"."

Here, the aarch64 VM crashes when executing an existing regression test.  And backporting the fix should be low in risk given that that this feature is rarely used so far. 
I am also worried that people with 8u may create new code or modify existing code making use of the critical JNI feature for performance reasons. 
Instead of crashing and possibly giving people the impression that the aarch64 VM is not quite stable, I think it will be better to tell them explicitly that this feature is not supported on this platform. 
I will let you 8u maintainers to decide. 

[1] https://wiki.openjdk.java.net/display/jdk8u/Guidelines+for+working+on+jdk8u

Thanks,
Felix