Still plagued by "Agent communication error"

Martin Buchholz martinrb at
Wed Aug 14 07:28:08 UTC 2019

On Tue, Aug 13, 2019 at 11:49 PM Alan Bateman <Alan.Bateman at>

> On 13/08/2019 23:39, Martin Buchholz wrote:
> > We continue to see rare "Agent communication error" problems when
> > running jtreg tests.
> > We believe something has gone wrong in the JDK under test, but we
> > never get any details.
> > The failure is correlated with running specific tests, and specific JDKs.
> > Anecdotally, it appears to be more common with fastdebug JDKs.
> >
> > A sample snippet:
> >
> > TEST RESULT: Error. Agent communication error:
> > Broken pipe (Write failed); check console
> > log for any additional details
> Are the agent VMs crashing? Maybe the fastdebug builds are hitting
> asserts earlier than the crash with product bits. Have you looked at
> hs_err logs or core files on the systems?

It's not so easy for us to get hs_err log files; we only get jtreg
While we could/should improve our infrastructure ...
jtreg provides helpful diagnostics in other cases, e.g. thread dump on test
timeout, so it would be good to be helpful even when communication with the
agent breaks down.  Maybe jtreg should use one of those VM flags to get
agent VMs to send failure data to stderr?
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