Re: SIGSEGV on isprime

[Ján Jančár <johny@neuromancer.sk>]

On 11/07/18 16:48, Ján Jančár wrote:
> On 11/07/18 16:32, Ján Jančár wrote:
>> On 11/07/18 16:03, Ján Jančár wrote:
>>> On 10/07/18 23:59, Bill Allombert wrote:
>>>> On Tue, Jul 10, 2018 at 06:35:40PM +0200, Ján Jančár wrote:
>>>>> ...
>>>>> I compiled pari 2.9.5 / 2.10.1 / current git master, with
>>>>> ./Configure --enable-tls -g
>>>>> and the error happens in all of the versions.
>>>>>
>>>>> Any ideas on what might be causing this? ldd of the binary on both
>>>>> machines shows the same libraries are used, so it is very mysterious to
>>>>> me that it works on one and not on the other.
>>>>
>>>> Why are you using --enable-tls ? Does it makes a difference ?
>>>> Are you using the same compiler ? The same processor ?
>>>> This code has not changed between 2.9.5 and 2.10.1, however it is rather
>>>> messy, so maybe it is not compiled correctly.
>>>> You can also try
>>>> ./Configure --kernel=none 
>>>>
>>>
>>> The application I am compiling requires tls, I will test it with the
>>> reproducer without tls but even if it works, it will be unusable for me.
>>> I am indeed using the same compiler, the only obvious difference I can
>>> think of is the processor.
>>>
>>> I have now tested:
>>>
>>> --enable-tls --kernel=none      --> works
>>> --enable-tls --kernel=none-gmp  --> SEGVs!
>>> --enalbe-tls --kernel=auto-none --> works
>>>
>>> Not sure what to make of this, I will try with a newer version of GMP,
>>> 6.0.0 is currently installed(on both machines, where it works and
>>> doesn't) but 6.1.2 is available, so I will see if that fixes it.
>>>
>>
>>
>> I have just tested with GMP 6.1.2 and the same SIGSEGV appears.
>> Interestingly enough, when doing
>> isprime(0x8d4731c77d346297e54306afea3730a1) in gp(statically or
>> dynamically linked) the computation is just fine, no SEGV.
>>
> 
> Hmm, doing:
> 
>> #include <pari/pari.h>
>> #include <stdio.h>
>>
>> int main(void) {
>>         pari_init(1000000000, 1000000);
>>         isprime(stoi(1));
>>         GEN order = strtoi("0x8d4731c77d346297e54306afea3730a1");
>>         long i = isprime(order);
>>         printf("%li\n", i);
>>         pari_close();
>>         return 0;
>> }
>>
> 
> Actually fixes the problem, still not sure how.
> 


Also, forgot to say that the number:
0x8d4731c77d346297e54306afea3730a1
is a Carmichael pseudoprime, which might have something to do with this
error.

Cheers,
-- 
Jan
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