[jdk17] RFR: JDK-8266310: deadlock between System.loadLibrary and JNI FindClass loading another class

[Chris Hegarty]

> On 24 Jun 2021, at 22:27, Mandy Chung <mchung at openjdk.java.net> wrote:
> 
> On Fri, 18 Jun 2021 09:50:49 GMT, Aleksei Voitylov <avoitylov at openjdk.org> wrote:
> 
>> Resubmitting the following PR https://github.com/openjdk/jdk/pull/3976 against JDK17.
>> 
>> This fixes the deadlock in ClassLoader between the two lock objects - a lock object associated with the class being loaded, and the ClassLoader.loadedLibraryNames hash map, locked during the native library load operation.
>> 
>> Further details can be found in the original PR.
>> 
>> Testing: jtreg and jck testing with no regressions. A new regression test was developed.
> 
> This is a risky area and I agree it needs some bake time. The fix has been ready for some time but it takes longer than we hope to get this reviewed and approved (I was one causing the delay).  I am not uncomfortable getting this in JDK 17 but I will  not object if others think this should be fixed in JDK 18 (and backport to 17 update if desirable) as this is a long standing issue and no urgency to get this fixed.

Fixing initially in 18, allowing some “bake” time, then considering a backport to a 17 update, seems prudent.

-Chris.