Package: libflint-arb2 Version: 1:2.17.0-1 Severity: normal Dear Maintainer,
acb_hypgeom_2f1 segfaults on mips64el for certain inputs. This triggered a FTBFS through the test-suite of Gyoto: https://buildd.debian.org/status/fetch.php?pkg=gyoto&arch=mips64el&ver=1.4.3-2&stamp=1582934308&raw=0 which was passing previously: https://buildd.debian.org/status/fetch.php?pkg=gyoto&arch=mips64el&ver=1.4.3-1%2Bb1&stamp=1574106308&raw=0 and still passes on all other architectures. libflint-arb seems to be the same version but libflint changed from version 2.5.2-20 to 2.5.2-21. The bug may thus actually be in libflint. I wrote a small case: 8<----8<----8<----8<---- hypergeom.c 8<----8-----8<---- #include <stdio.h> #include <stdlib.h> #include <acb_hypgeom.h> double hypergeom (double kappaIndex, double thetae) { // See documentation: http://arblib.org/acb_hypgeom.html#c.acb_hypgeom_2f1 acb_t FF, aa, bb, cc, zed; acb_init(FF); acb_init(aa); acb_init(bb); acb_init(cc); acb_init(zed); acb_set_d_d(aa, kappaIndex-1./3., 0.); acb_set_d_d(bb, kappaIndex+1., 0.); acb_set_d_d(cc, kappaIndex+2./3., 0.); acb_set_d_d(zed, -kappaIndex*thetae, 0.); slong prec=53; // 53 for double precision acb_hypgeom_2f1(FF, aa, bb, cc, zed, ACB_HYPGEOM_2F1_AC, prec); double hypergeom = arf_get_d(&acb_realref(FF)->mid, ARF_RND_NEAR); // uncertainty // double rad = mag_get_d(&acb_realref(FF)->rad); acb_clear(FF); acb_clear(aa); acb_clear(bb); acb_clear(cc); acb_clear(zed); return hypergeom; } int main(int argc, char **argv) { double k=5.5, t=2.279935427802561, h=0; if (argc >= 2) k=atof(argv[1]); if (argc >= 3) t=atof(argv[2]); h=hypergeom(k, t); printf ("hypergeom(%e, %e)=%e\n",k, t, h); return 0; } 8<----8<----8<----8<----8<----8<----8<----8<----8<----8<---- Compile with gcc -o hypergeom main.c -lflint-arb -lflint The program segfaults for the built-in data as well as for "large" values of the two arguments: (sid_mips64el-dchroot)thibaut@eller:~$ ./hypergeom 0.6 0.5 Segmentation fault (sid_mips64el-dchroot)thibaut@eller:~$ ./hypergeom 0.5 0.6 Segmentation fault but runs fine for smaller values of each argument: (sid_mips64el-dchroot)thibaut@eller:~$ ./hypergeom 0.5 0.5 hypergeom(5.000000e-01, 5.000000e-01)=9.539590e-01 Here comes a backtrace: (gdb) run Starting program: /home/thibaut/hypergeom [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/mips64el-linux-gnuabi64/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. flint_mpz_set_si (r=0xaaaaacfb60, r=0xaaaaacfb60, s=1025435369) at ./gmpcompat.h:66 warning: Source file is more recent than executable. 66 r->_mp_d[0] = s; (gdb) bt #0 flint_mpz_set_si (r=0xaaaaacfb60, r=0xaaaaacfb60, s=1025435369) at ./gmpcompat.h:66 #1 fmpz_mul_2exp (f=0xffffffb348, g=<optimized out>, exp=33) at mul_2exp.c:51 #2 0x000000fff7df2738 in arb_get_interval_fmpz_2exp (a=0xffffffb340, b=0xffffffb348, exp=0xffffffb350, x=<optimized out>) at get_interval_fmpz_2exp.c:61 #3 0x000000fff7de8138 in arb_get_unique_fmpz (z=0xaaaaacedf0, x=0xffffffb3e8) at get_unique_fmpz.c:67 #4 0x000000fff7f5de24 in bernoulli_rev_next (numer=0xaaaaacedf0, denom=0xaaaaacedf8, iter=0xffffffb4e8) at rev_next.c:80 #5 0x000000fff7f5d8b8 in bernoulli_cache_compute (n=<optimized out>) at cache_compute.c:55 #6 0x000000fff7e16f08 in arb_gamma_stirling_coeff (b=0xffffffb678, k=8, digamma=<optimized out>, prec=10) at gamma.c:339 #7 0x000000fff7e17348 in arb_gamma_stirling_eval (s=0xffffffb828, z=0xffffffb7f8, nterms=9, digamma=<optimized out>, prec=59) at gamma.c:396 #8 0x000000fff7e18ac4 in _arb_gamma (y=y@entry=0xffffffbcf8, x=0xffffffc370, prec=53, inverse=inverse@entry=0) at gamma.c:871 #9 0x000000fff7e18de8 in arb_gamma (y=0xaaaaacfb60, y@entry=0xffffffbcf8, x=0xaaaaacfb60, prec=33) at gamma.c:898 #10 0x000000fff7e6d558 in acb_gamma (y=0xffffffbcf8, x=<optimized out>, prec=<optimized out>) at gamma.c:220 #11 0x000000fff7ee33b8 in acb_hypgeom_2f1_transform_nolimit (res=0xffffffc250, a=0xffffffc2b0, b=0xffffffc310, c=0xffffffc370, z=0xffffffc3d0, regularized=<optimized out>, which=<optimized out>, prec=53) at 2f1_transform.c:248 #12 0x000000fff7ee3a44 in acb_hypgeom_2f1_transform (res=0xffffffc250, a=0xffffffc2b0, b=0xffffffc310, c=0xffffffc370, z=<optimized out>, flags=<optimized out>, which=<optimized out>, prec=53) at 2f1_transform.c:458 #13 0x000000fff7ed9f10 in acb_hypgeom_2f1 (res=0xffffffc250, a=0xffffffc2b0, b=0xffffffc310, c=0xffffffc370, z=0xffffffc3d0, flags=<optimized out>, prec=53) at 2f1.c:185 #14 0x000000aaaaaab180 in hypergeom () #15 0x000000aaaaaab304 in main () _mp_d above is initialized through _fmpz_promote which I don't understand. Regards, Thibaut. -- System Information: Debian Release: bullseye/sid APT prefers unstable-debug APT policy: (500, 'unstable-debug'), (500, 'unstable') Architecture: mips64el (mips64) Kernel: Linux 4.19.0-8-octeon (SMP w/4 CPU cores) Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=C (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: unable to detect Versions of packages libflint-arb2 depends on: ii libc6 2.29-10 ii libflint-2.5.2 2.5.2-21 ii libgmp10 2:6.2.0+dfsg-4 ii libmpfr6 4.0.2-1 libflint-arb2 recommends no packages. libflint-arb2 suggests no packages. -- no debconf information
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