JEP 498: Warn upon Use of Memory-Access Methods in sun.misc.Unsafe

[tajila]

See https://openjdk.org/jeps/498

[github-actions]

Issue Number: 20632
Status: Open
Recommended Components: comp:vm, comp:gc, comp:jclextensions

[tajila]

I expect it to land by next week.

[theresa-m]

I don't think there is any vm work to do here. I will run the OpenJ9 functional tests with --sun-misc-unsafe-memory-access=warn to see if any tests will fail once it becomes the default setting.

[theresa-m]

There were no test failures with --sun-misc-unsafe-memory-access=warn on. I think this issue can be closed.

• Sanity https://hyc-runtimes-jenkins.swg-devops.com/view/Test_grinder/job/Grinder_Simple/37/
• Extended https://hyc-runtimes-jenkins.swg-devops.com/view/Test_grinder/job/Grinder_Simple/38/

[github-actions]

Issue Number: 20632
Status: Closed
Actual Components: comp:vm, JEP
Actual Assignees: No one :(
PR Assignees: No one :(

[pshipton]

I would be good to run openjdk testing as well.

What happens if we run with --sun-misc-unsafe-memory-access=deny? If there is usage from OpenJ9 class library code that is going to generate warnings, I think it needs to be removed so user's don't get these warnings.

[theresa-m]

I'll try with openjdk tests and --sun-misc-unsafe-memory-access=deny as well.

OpenJ9 does not generate any warning for this, it is done in https://github.com/openjdk/jdk/blob/master/src/jdk.unsupported/share/classes/sun/misc/Unsafe.java#L1860

[pshipton]

The point is that OpenJ9 implements JCL code that uses Unsafe. If this code ends up generating a warning when run in a user application, this needs to be fixed.

[hzongaro]

The point is that OpenJ9 implements JCL code that uses Unsafe. If this code ends up generating a warning when run in a user application, this needs to be fixed.

Does the OpenJ9 JCL code after version 8 use sun.misc.Unsafe or only jdk.internal.misc.Unsafe? Will warnings be reported for uses of either or only the former?

[pshipton]

I think in theory it's all fine since OpenJ9 should (can) only use jdk.internal.misc.Unsafe.

[theresa-m]

I tried sanity and extended tests with --sun-misc-unsafe-memory-access=deny
https://hyc-runtimes-jenkins.swg-devops.com/view/Test_grinder/job/Grinder_Simple/39/
https://hyc-runtimes-jenkins.swg-devops.com/view/Test_grinder/job/Grinder_Simple/40/

The 3 test failures are all due to direct uses of the sun.misc.Unsafe library.

• Test_UnsafeFence.testIntFence
• Test_UnsafeFence.testLongFence
• Cmvc199515.testCmvc199515

I'll try OpenJDK tests next.

[theresa-m]

OpenJdk sanity tests has a failure in sun/misc/UnsafeMemoryAccessWarnings.java.UnsafeMemoryAccessWarnings which is being updated in OpenJDK.
https://hyc-runtimes-jenkins.swg-devops.com/view/Test_grinder/job/Grinder/45102/

@pshipton is there anything else to try before resolving this issue?

[pshipton]

I can't think of anything else. Thanks for double checking.

[github-actions]

Issue Number: 20632
Status: Closed
Actual Components: comp:vm, JEP
Actual Assignees: No one :(
PR Assignees: No one :(