Hello,
could you try with a recent snapshot from
https://gmplib.org/download/snapshot/ ?
If you built GMP yourself, did you run `make check` afterwards?
On Thu, 8 Jun 2023, Philip Riebold wrote:
Hi,
I think I may have come across an error in mpz_probab_prime_p() It seems to
occasionally cause a segmentation fault either when repeatedly run with the
same arguments or with increasing values of the first argument.
I initially came across the bug when I was trying to find the closest primes
10^n, 2*10^n or 5*10^n when the program would crash after listing the
first
few dozen/hundred results.
The platform is a 16GB M2 Mac Air.
The test program below, pt3.c is the simplest I could produce to demonstrate
the problem.
The first argument 20000000000000000011 is the smallest value I found which
caused the error.
When I ran pt3 100 times the for() loop executed between 4 and 4684 times
before crashing.
GMP version 6.2.1
=====================
Philip:gmp_error philip$ cat pt3.c
#include <stdio.h>
#include <string.h>
#include <gmp.h>
int main(void)
{
setbuf(stdout,NULL);
mpz_t test;
for(int n = 1; n <= 1000; n++) {
printf("%4d\n", n);
mpz_init(test);
mpz_set_str(test, "20000000000000000011", 10);
int res = mpz_probab_prime_p(test, 100);
mpz_clear(test);
if(res != 1)
printf("res = %d\n", res);
}
printf("hmmm, it hasn't failed\n");
}
Philip:gmp_error philip$
=====================
Philip:gmp_error philip$ cc -v
Apple clang version 14.0.3 (clang-1403.0.22.14.1)
Target: arm64-apple-darwin22.5.0
Thread model: posix
InstalledDir:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
Philip:gmp_error philip$
=====================
Philip:gmp_error philip$ uname -a
Darwin Philip 22.5.0 Darwin Kernel Version 22.5.0: Mon Apr 24 20:52:43 PDT
2023; root:xnu-8796.121.2~5/RELEASE_ARM64_T8112 arm64
Philip:gmp_error philip$
=====================
Philip:gmp-6.2.1 philip$ ./config.guess
aarch64-apple-darwin22.5.0
Philip:gmp-6.2.1 philip$
=====================
Philip:gmp-6.2.1 philip$ ./configfsf.guess
aarch64-apple-darwin22.5.0
Philip:gmp-6.2.1 philip$
=====================
Philip:gmp_error philip$ cc -o pt3 pt3.c -lgmp
Philip:gmp_error philip$ ./pt3
1
2
3
4
⋮
143
144
145
146
Segmentation fault: 11
Philip:gmp_error philip$
=====================
If there's anything I can do to help please ask.
TTFN
Philip Riebold
--
Marc Glisse
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