RFR: 8072701: resume001 failed due to ERROR: timeout for waiting for a BreakpintEvent

[Alex Menkov]

On Wed, 10 Jul 2024 20:50:50 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> I was finally able to reproduce the issue with the stack dumping support in place. mainThread is in the middle of printing the 1st of the two logs mention above. mainThead is suspended and is holding a println related lock, and thread2 is stuck on the 2nd log call in runt2 awaiting the same lock.
>
> I was able to add synchronization between the debugger and debuggee to fix this issue, but I don't really like the solution. It just adds more complexity and makes the test even harder to follow. What I'd like to do is just put a short sleep in before the vm.suspend(). Let me know if you think this is ok and I'll update the PR with the changes.

Thank you for the confirming the reason of the timeout.

To be more clear about my point:
The test has 3 scenarios (see the test description):
ThreadReference.resume() resumes the thread suspended with:
 *   - with thread2.suspend()                                           <BR>
 *   - at a breakpoint                                                  <BR>
 *   - with VirtualMachine.suspend()                                    <BR>

So for 3rd scenario we should not call vm.resume() (as it converts 3rd scenario to 1st scenario).
The test can be fixed by different ways, to me remove logging between breakpoint2 and breakpoint3 is the simplest way.
Note that breakpoint2 is "runt2(), line 2" and breakpoint3 is "runt1(), line 7", there are 2 log statements. We can move breakpoint 3 to "runt2(), line 3" (I don't see much sense to have breakpoint 3 so far from breakpoint2 - we just need to ensure the thread was resumed )

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PR Review Comment: https://git.openjdk.org/jdk/pull/20088#discussion_r1672989677