RFR: 8292695: SIGQUIT and jcmd attaching mechanism does not work with signal chaining library [v3]

[Man Cao]

On Fri, 9 Sep 2022 05:21:13 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> The SIGBREAK handler does not seem to honor `-XX:+AllowUserSignalHandlers`. It is still installed even with `-XX:+AllowUserSignalHandlers`.
>> 
>> Perhaps it can be addressed separately later? As commented in https://bugs.openjdk.org/browse/JDK-8293466, I haven't seen a real use case for +AllowUserSignalHandlers, so I'd vote for deprecating `AllowUserSignalHandlers` for removal in the future.
>
> Okay for separate addressing. Deprecating may not be an option though, depending on how seriously we take backward compatibility.

Thanks. Filed https://bugs.openjdk.org/browse/JDK-8293580.

>> https://docs.oracle.com/en/java/javase/17/troubleshoot/handle-signals-and-exceptions.html#GUID-CB49A2A7-2A9F-4C18-948F-6D4A96FF688D says signal chaining is available only on Linux and macOS. Should the doc be updated?
>> 
>> Also, the tests in `test/hotspot/jtreg/runtime/signal/` have "!windows && !aix". I'm not sure why they exclude aix, should this test exclude aix similarly?
>
> Well, Solaris support was removed from JDK in 16, but older releases still support it, see: https://docs.oracle.com/en/java/javase/11/troubleshoot/handle-signals-and-exceptions.html#GUID-F012840D-8E5A-4B6D-8E49-0129A9EE46DB.
> 
> As  for AIX, the reason given for the exclusions in other tests is that we cannot run in the primordial thread on AIX. That is true but I'm not sure what this has to do with the signal tests, and I believe libjsig and the other stuff should just work on AIX. I have to dig in our older sources (this stems from the pre-OpenJDK times at SAP).
> 
> For now, I'd use !windows && !aix. AIX we can take care of later, but Solaris I would like to support here. Because of backporting, mainly.

Done. Thanks for the details!

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PR: https://git.openjdk.org/jdk/pull/9955