Re: fairywren failures

Hi,

On 2019-10-03 10:21:13 -0400, Andrew Dunstan wrote:
> My new msys2 animal fairywren has had 3 recent failures when checking
> pg_upgrade. The failures have been while running the regression tests,
> specifically the interval test, and they all look like this:
>
>
> 2019-10-03 05:36:00.373 UTC [24272:43] LOG: server process (PID 23756) was terminated by exception 0xC0000028
> 2019-10-03 05:36:00.373 UTC [24272:44] DETAIL: Failed process was running: INSERT INTO INTERVAL_TBL (f1) VALUES ('badly formatted interval');
>
>
> That error is "bad stack"

> The failures have been on REL_12_STABLE (twice) and master (once).
> However, they are not consistent (REL_!2_STABLE is currently green).
>
>
> The interval test itself hasn't changed for m ore than 2 years, and I
> haven't found any obvious recent change that might cause the problem. I
> guess it could be a comoiler bug ... this is gcc 9.2.0, which is the
> current release.

This is around where an error is thrown:
-- badly formatted interval
INSERT INTO INTERVAL_TBL (f1) VALUES ('badly formatted interval');
-ERROR: invalid input syntax for type interval: "badly formatted interval"
-LINE 1: INSERT INTO INTERVAL_TBL (f1) VALUES ('badly formatted inter...
- ^

and the error is stack related. So I suspect that setjmp/longjmp might
be to blame here, and somehow don't save/restore the stack into a proper
state. I don't know enough about mingw/msys/windows to know whether that
uses a self-written setjmp or relies on the MS implementation.

If you could gather a backtrace it might help us. It's possible that the
stack is "just" misaligned or something, we had problems with that
before (IIRC valgrind didn't always align stacks correctly for processes
that forked from within a signal handler, which then crashed when using
instructions with alignment requirements, but only sometimes, because
the stack coiuld be aligned).

Greetings,

Andres Freund