[8u] RFR 8252904: VM crashes when JFR is used and JFR event class is transformed

[Andrew Dinn]

Hi Andrey,

On 08/09/2020 17:39, Andrey Petushkov wrote:

> updated webrev https://cr.openjdk.java.net/~apetushkov/8252904.01/

Thanks. That looks better. I agree that aligning the resource mark with
the lifetime of the ClassFileParser instance is the correct model.

Of course, in SystemDictionary::resolve_from_stream that lifetime is
longer than it needs to be. However, fixing that is not needed to deal
with the bug so I'm more than happy to leave well alone, minimizing
perturbation of the existing code.

>>> Last but not least, what have you done to test this patch?
>> We have a proprietary though simple test which instruments all the java
>> classes loaded into VM. I've used this test in conjunction with the
>> slowdebug VM to test the fix. As mentioned, the VM crashes reliably
>> without a fix, while successfully working with it (given the nature of
>> the test it in fact verifies not only that JFR event classes can now be
>> instrumented successfully, but also serves some sanity check that all
>> other class loads happened via other code paths are not affected, to the
>> extent the slowdebug VM assertions can verify)
>>
>> I cannot publish the source code of a test but if necessary I can
>> prepare a minimal reproducer
Yes, please.

regards,


Andrew Dinn
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