Bill Allombert on Sat, 18 Oct 2025 11:03:05 +0200


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: PARI/GP 2.17.2 testsuite hangs nondeterministically (macOS)


On Fri, Oct 17, 2025 at 03:18:35PM -0700, Matthias Koeppe wrote:
> I am encountering nondeterministic hangs of PARI/GP while running its
> testsuite on macOS. It seems to happen in particular in higher CPU
> load situations.
> The hang appears to be a pthread deadlock. In both of the tests that I
> have seen affected by it (bnf, ellrank), the backtrace shows
> "ZM_gauss", via "gen_inccrt_i". More detail:

((Are you sure it is ellrank ? It looks more like ellnf))

Clearly it hangs in mt_queue_reset while waiting for threads to terminate.

> https://github.com/passagemath/passagemath/issues/1684

This report does not include any detail on the system platform.
(what is the CPU, the OS version, the libc version, the compiler version etc.)

We run the full PARI test suite with  --mt=pthread on aarch64 MacOS 12.0 on a
M1 every day and we never noticed any hangs. Maybe they happen without us
noticing thought.  The latest buildlog is 
<https://pari.math.u-bordeaux.fr/buildlogs/caa3445f-35dd-4ced-86be-e830cd259888>

PARI does not use OpenMP so setting OMP_NUM_THREADS should not have any effect.

Cheers,
Bill.