RFR 8249217: Unexpected StackOverflowError in "process reaper" thread still happens

[Roger Riggs]

Hi Martin,

That's a good idea, but unless I miss your point, there is no Reaper class,
only a lambda that is used as to create the Executor for the reaper 
thread pool.

Do you mean to put it before or after lines 91-93?  [1]

Thanks, Roger

[1] 
http://cr.openjdk.java.net/~rriggs/webrev-stackoverflow-8249217/src/java.base/share/classes/java/lang/ProcessHandleImpl.java.sdiff.html


On 7/22/20 8:06 PM, Martin Buchholz wrote:
> Looks good.
>
> I might move the static class preloading into a static method of the
> reaper thread class, to make it clearly the responsibility of the
> reaper thread class to enumerate and pre-load its dependencies.
>
> On Wed, Jul 22, 2020 at 7:59 AM Peter Levart <peter.levart at gmail.com> wrote:
>> Hi Roger,
>>
>>
>> I don't think resolving the ConcurrentHashMap.class ensures
>> initialization of the class. Just loading. But I think CHM is already
>> initialized at that time as it is used in ClassLoader to maintain class
>> loading locks (per class name).
>>
>>
>> Regards, Peter
>>
>>
>> On 7/22/20 4:51 PM, Roger Riggs wrote:
>>> Please review a change to the Process reaper thread initialization to
>>> preemptively
>>> make sure classes ThreadLocalRandom and ConcurrentHashMap are
>>> initialized.
>>>  From the stack overflow failures, it seems that the classes have not
>>> been initialized
>>> before they are used during processing the termination of a process.
>>> When the initialization is performed on the smaller reaper stack, it
>>> occasionally
>>> exceeds the available stack.
>>>
>>> As an aid to diagnostics,
>>> -XX:AbortVMOnException=java.lang.StackOverflowError
>>> is added to TestHumongousNonArrayAllocation that has failed
>>> intermittently.
>>> If the problem happens again it will produce an hs_error file with
>>> useful details
>>> and will otherwise not change the test behavior.
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~rriggs/webrev-stackoverflow-8249217/
>>>
>>> Issue:
>>>    https://bugs.openjdk.java.net/browse/JDK-8249217
>>>
>>> Thanks, Roger
>>>