RFR: 8295099: vmTestbase/nsk/stress/strace/strace013.java failed with "TestFailure: wrong lengths of stack traces: strace013Thread0: NNN strace013Thread83: MMM"

[David Holmes]

On Mon, 7 Nov 2022 05:37:50 GMT, David Holmes <dholmes at openjdk.org> wrote:

> The test is incorrectly synchronized and may take the stack trace of a thread before it has entered the wait() and thus be three frames short of the correct stack. So I cleaned that up to ensure things are correctly synchronized.
> 
> A number of comments in the test description etc were wrong so I also fixed those.
> 
> These tests are stylistically awful but I refrained from embarking on a major cleanup and adopted the prevailing styles.
> 
> Testing: local plus 50x on each platform (in progress)
> 
> Thanks.

I changed things to remove the "k-2" slack, but also note that if a spurious wakeup were ever to occur then the test could again fail. I think the slack was misguided and should have been 3 - but in that case I fail to see the point of this test. If we get rare failures in the future I would advocate for the removal of this test.

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PR: https://git.openjdk.org/jdk/pull/11011