RFR JDK-8170089: nsk/jdi/EventSet/resume/resume008: ERROR: suspendCounts don't match for : Common-Cleaner
Gary Adams
gary.adams at oracle.com
Tue Aug 28 12:20:38 UTC 2018
I went back and confirmed that the debuggeeClass initialization in
TestDebuggerType1 RunThis() method happens very early on in the
test setup. If it was not initialized, the very first attempts to set the
breakpoint for communication would have failed.
So this usage after a first test case is completed would never be null.
I've removed that check and attached a patch that should be ready to
push.
On 8/27/18, 4:26 PM, Chris Plummer wrote:
> Hi Gary,
>
> Just getting caught up again. To answer your earlier question, yes, I
> think removing the isDisconnected() check is an improvement since it's
> use was at best inconsistent, and leads the reader to think that this
> is something that is expected to happen. If it does happen, the test
> will still fail in an appropriate way, and adding the check can
> actually hide the failure.
>
> And looking at this again, I'm now wondering about the debuggeeClass
> != null check. Is it possible for it to ever be null? That kind of
> seems along the lines of the isDisconnected() check.
>
> Other than that the changes look fine.
>
> thanks,
>
> Chris
>
> On 8/24/18 5:32 AM, Gary Adams wrote:
>> Here's an updated webrev with the isDisconnected checks removed
>> in the setValue handling.
>>
>> http://cr.openjdk.java.net/~gadams/8170089/webrev.02/index.html
>>
>> Testing is in progress, but no failed tests have shown up so far
>> with the extra check removed.
>>
>> On 8/22/18, 1:05 PM, Gary Adams wrote:
>>> On 8/6/18, 3:16 PM, Chris Plummer wrote:
>>>> On 8/6/18 11:41 AM, Gary Adams wrote:
>>>>> On 8/6/18, 1:56 PM, Chris Plummer wrote:
>>>>>> On 8/6/18 4:16 AM, Gary Adams wrote:
>>>>>>> On 8/3/18, 6:38 PM, Chris Plummer wrote:
>>>>>>>> Hi Gary,
>>>>>>>>
>>>>>>>> Overall it looks good.
>>>>>>>>
>>>>>>>> Is the EventHandler.isDisconnected() check needed?
>>>>>>> This just follows the pattern used in other calls to setValue.
>>>>>> I'm not seeing any other examples of this. Can you point me to
>>>>>> them? Isn't it expected that you will always be connected, and it
>>>>>> will only be disconnected if there is something very wrong with
>>>>>> the execution of the test? Not producing an error in that case
>>>>>> could actually be misleading, causing the test to fail with some
>>>>>> sort of state related error rather than some sort of exception
>>>>>> indicating it was disconnected.
>>>>> The best examples of checking EventHandler.isDisconnected()
>>>>> can be seen in the implementation of shouldRunAfterBreakPoint()
>>>>> See
>>>>> test/hotspot/jtreg/vmTestbase/nsk/share/jdi/TestDebuggerType1.java
>>>>>
>>>>> It's used in the loop waiting for the breakpoint event to be
>>>>> observed,
>>>>> and in the getValue() fetching of the next "instruction" indicating
>>>>> testing is completed.
>>>> Well, that's just 2 uses of isDisconnected() out of the 200+
>>>> get/setValue() calls. I can see its use in the loop, since it is
>>>> used to force the exit of the loop when disconnected (rather than
>>>> waiting for timeout). The one before the getValue() call is more
>>>> like your use, and I don't see the need in this case either. What's
>>>> to prevent becoming disconnected between the isDisconnected() and
>>>> the get/setValue() call?
>>>
>>> Just following up on this loose end after vacation ...
>>>
>>> I agree that there is nothing preventing the connection being
>>> terminated
>>> between the time isDisconnected() is checked and the call to setValue()
>>> being made. I also don't see any harm in including the isDisconnected()
>>> check here. If you think the test is improved by removing the check,
>>> I'll make those changes, post a fresh webrev and repeat the testing.
>>>>
>>>> Chris
>>>>>>
>>>>>> Chris
>>>>>>> No point in attempting the operation, if you know the
>>>>>>> connection was lost. An exception at this point could
>>>>>>> be misleading, if some other error has already occurred.
>>>>>>>>
>>>>>>>> In resume008a.java you removed a lot of empty lines. In some
>>>>>>>> places it's fine, but the lines at 132 and 134 should have
>>>>>>>> remained. Also, for the ones that were ok to remove, I don't
>>>>>>>> see you doing the same thing in the other files. I think
>>>>>>>> probably it's best to be consistent, and for this webrev
>>>>>>>> probably best not to do them since it distracts too much from
>>>>>>>> the important changes.
>>>>>>> The original bug was reported against resume008, so more time
>>>>>>> was spent in that
>>>>>>> particular test, including some line wrapping changes. I will
>>>>>>> restore the blank lines
>>>>>>> you mentioned before producing a final patch. The other tests
>>>>>>> had observed failures
>>>>>>> also during testing. Applying the same change fixed those
>>>>>>> failures as well.
>>>>>>>>
>>>>>>>> Seems like there is a lot of abstraction that could have been
>>>>>>>> done with these tests to share a lot of code, but since so far
>>>>>>>> that hasn't been done, probably not a good idea to start doing
>>>>>>>> that with this fix. Do you think it's worth filing an
>>>>>>>> enhancement request for?
>>>>>>> Reformatting or refactoring these older tests would be at best a
>>>>>>> P5.
>>>>>>> I don't think it's worth filing a bug, but as we fix bugs in
>>>>>>> these test it's
>>>>>>> worth some minimal amount of cleanup while we are in the code.
>>>>>>>>
>>>>>>>> thanks,
>>>>>>>>
>>>>>>>> Chris
>>>>>>>>
>>>>>>>> On 8/3/18 11:04 AM, Gary Adams wrote:
>>>>>>>>> Here is an updated webrev with the alternate solution
>>>>>>>>> implemented for
>>>>>>>>> resume 1 to 10. The debugger sets testCase variable in the
>>>>>>>>> debuggee
>>>>>>>>> when each test case completes in the debugger. By having the
>>>>>>>>> debuggee
>>>>>>>>> wait for the debugger to complete with test case 0, it avoids
>>>>>>>>> the interference
>>>>>>>>> that occurs by proceeding to the breakpoint set in
>>>>>>>>> MethodForCommunication
>>>>>>>>> before the debugger has compared expected suspend counts.
>>>>>>>>>
>>>>>>>>> Webrev:
>>>>>>>>> http://cr.openjdk.java.net/~gadams/8170089/webrev.01/index.html
>>>>>>>>>
>>>>>>>>> On 7/17/18, 11:33 AM, Gary Adams wrote:
>>>>>>>>>> A race condition exists between the debugger and the debuggee.
>>>>>>>>>>
>>>>>>>>>> The first test thread is started with SUSPEND_NONE policy set.
>>>>>>>>>> While processing the thread start event the debugger captures
>>>>>>>>>> an initial set of thread suspend counts and resumes the
>>>>>>>>>> debuggee vm. If the debuggee advances quickly it reaches
>>>>>>>>>> the breakpoint set for methodForCommunication. Since the
>>>>>>>>>> breakpoint
>>>>>>>>>> carries with it SUSPEND_ALL policy, when the debugger
>>>>>>>>>> captures a second
>>>>>>>>>> set of suspend counts, it will not match the expected counts for
>>>>>>>>>> a SUSPEND_NONE scenario.
>>>>>>>>>>
>>>>>>>>>> The proposed fix introduces a yield in the debuggee test
>>>>>>>>>> thread run method
>>>>>>>>>> to allow the debugger to get the expected sampled values.
>>>>>>>>>>
>>>>>>>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8170089
>>>>>>>>>> Webrev: http://cr.openjdk.java.net/~gadams/8170089/webrev.00/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> test/hotspot/jtreg/vmTestbase/nsk/share/jdi/TestDebuggerType1.java:
>>>>>>>>>>
>>>>>>>>>> ...
>>>>>>>>>> 186 private void
>>>>>>>>>> setCommunicationBreakpoint(ReferenceType refType, String
>>>>>>>>>> methodName) {
>>>>>>>>>> 187 Method method =
>>>>>>>>>> debuggee.methodByName(refType, methodName);
>>>>>>>>>> 188 Location location = null;
>>>>>>>>>> 189 try {
>>>>>>>>>> 190 location =
>>>>>>>>>> method.allLineLocations().get(0);
>>>>>>>>>> 191 } catch (AbsentInformationException e) {
>>>>>>>>>> 192 throw new Failure(e);
>>>>>>>>>> 193 }
>>>>>>>>>> 194 bpRequest = debuggee.makeBreakpoint(location);
>>>>>>>>>> 195
>>>>>>>>>>
>>>>>>>>>> 196 bpRequest.setSuspendPolicy(EventRequest.SUSPEND_ALL);
>>>>>>>>>>
>>>>>>>>>> 197 bpRequest.putProperty("number", "zero");
>>>>>>>>>> 198 bpRequest.enable();
>>>>>>>>>> 199
>>>>>>>>>> 200 eventHandler.addListener(
>>>>>>>>>> 201 new EventHandler.EventListener() {
>>>>>>>>>> 202 public boolean eventReceived(Event
>>>>>>>>>> event) {
>>>>>>>>>> 203 if (event instanceof
>>>>>>>>>> BreakpointEvent && bpRequest.equals(event.request())) {
>>>>>>>>>> 204 synchronized(eventHandler) {
>>>>>>>>>> 205 display("Received communication breakpoint event.");
>>>>>>>>>> 206 bpCount++;
>>>>>>>>>> 207 eventHandler.notifyAll();
>>>>>>>>>> 208 }
>>>>>>>>>> 209 return true;
>>>>>>>>>> 210 }
>>>>>>>>>> 211 return false;
>>>>>>>>>> 212 }
>>>>>>>>>> 213 }
>>>>>>>>>> 214 );
>>>>>>>>>> 215 }
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> test/hotspot/jtreg/vmTestbase/nsk/jdi/EventSet/resume/resume008.java:
>>>>>>>>>>
>>>>>>>>>> ...
>>>>>>>>>> 140 display("......--> vm.suspend();");
>>>>>>>>>> 141 vm.suspend();
>>>>>>>>>> 142
>>>>>>>>>> 143 display(" getting :
>>>>>>>>>> Map<String, Integer> suspendsCounts1");
>>>>>>>>>> 144
>>>>>>>>>> 145 Map<String, Integer>
>>>>>>>>>> suspendsCounts1 = new HashMap<String, Integer>();
>>>>>>>>>> 146 for (ThreadReference
>>>>>>>>>> threadReference : vm.allThreads()) {
>>>>>>>>>> 147 suspendsCounts1.put(threadReference.name(),
>>>>>>>>>> threadReference.suspendCount());
>>>>>>>>>> 148 }
>>>>>>>>>> 149 display(suspendsCounts1.toString());
>>>>>>>>>> 150
>>>>>>>>>> 151 display(" eventSet.resume;");
>>>>>>>>>> 152 eventSet.resume();
>>>>>>>>>> 153
>>>>>>>>>> 154 display(" getting :
>>>>>>>>>> Map<String, Integer> suspendsCounts2");
>>>>>>>>>>
>>>>>>>>>> This is where the breakpoint is encountered before the second
>>>>>>>>>> set of suspend counts is acquired.
>>>>>>>>>>
>>>>>>>>>> 155 Map<String, Integer>
>>>>>>>>>> suspendsCounts2 = new HashMap<String, Integer>();
>>>>>>>>>> 156 for (ThreadReference
>>>>>>>>>> threadReference : vm.allThreads()) {
>>>>>>>>>> 157 suspendsCounts2.put(threadReference.name(),
>>>>>>>>>> threadReference.suspendCount());
>>>>>>>>>> 158 }
>>>>>>>>>> 159 display(suspendsCounts2.toString());
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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