RFR: JDK-8204994: SA might fail to attach to process with "Windbg Error: WaitForEvent failed"

[Alex Menkov]

Hi Serguei,

ok, I added the loop.
webrev:
http://cr.openjdk.java.net/~amenkov/jdk15/WinDbg_WaitForEvent/webrev.2/

--alex

On 05/28/2020 20:35, serguei.spitsyn at oracle.com wrote:
> Hi Alex,
> 
> It'd be nice to reduce noise from such intermittent issues and also get 
> rid of such bugs in the future.
> My gut feeling is that we just significantly reduced a probability of 
> this failure in something
> like an order of magnitude but it will still happens once in a month or 
> a half of year.
> This issue should go away completely with 3 or 4 iterations.
> The price is not high as the 3rd iteration is going to be rare and the 
> 4th should never happen.
> Also, it would not increase complexity.
> 
> But no pressure, you are to decide.
> I'm just sharing my opinion.
> 
> Thanks,
> Serguei
> 
> 
> On 5/28/20 17:04, Alex Menkov wrote:
>> Hi Serguei,
>>
>> With my testing 2nd call always succeeded, but I was able to reproduce 
>> the case only 3 times with my test runs.
>> I can implement the loop, but number of retries is anyway an arbitrary 
>> value.
>>
>> --alex
>>
>> On 05/28/2020 15:44, serguei.spitsyn at oracle.com wrote:
>>> Hi Alex,
>>>
>>> It looks good in general.
>>>
>>> +static HRESULT WaitForEvent(IDebugControl *ptrIDebugControl) {
>>> + // see JDK-8204994: sometimes WaitForEvent fails with E_ACCESSDENIED,
>>> + // but succeeded on 2nd call.
>>> + HRESULT hr = ptrIDebugControl->WaitForEvent(DEBUG_WAIT_DEFAULT, 
>>> INFINITE);
>>> + if (hr == E_ACCESSDENIED) {
>>> + // yield current thread use of a processor (short delay).
>>> + SwitchToThread();
>>> + hr = ptrIDebugControl->WaitForEvent(DEBUG_WAIT_DEFAULT, INFINITE);
>>> + }
>>> + return hr;
>>> +}
>>>
>>>
>>> Can the ptrIDebugControl->WaitForEvent fail with E_ACCESSDENIED twice 
>>> and succeed on third call?
>>> Would it better to make it a loop with more retry attempts?
>>>
>>> Thanks,
>>> Serguei
>>>
>>>
>>> On 5/27/20 13:54, Alex Menkov wrote:
>>>> Hi all,
>>>>
>>>> please review the fix for
>>>> https://bugs.openjdk.java.net/browse/JDK-8204994
>>>> webrev:
>>>> http://cr.openjdk.java.net/~amenkov/jdk15/WinDbg_WaitForEvent/webrev/
>>>>
>>>> --alex
>>>
>