On Wed, 28 Apr 2021, Jeff Epler wrote:
The attached program creates a rather large number, then attempts to print
it. The printing step encounters a segmentation fault.
Typical error traceback as seen by gdb:
Program received signal SIGSEGV, Segmentation fault.
__memmove_avx_unaligned_erms () at
../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:500
500 ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S: No such file
or directory.
(gdb) where
#0 __memmove_avx_unaligned_erms () at
../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:500
#1 0x000055555555cb3c in __gmp_asprintf_memory (d=0x7fffffffe2e0,
str=0x7ffeff624010 "", len=18446744071562067968) at asprntffuns.c:48
#2 0x000055555555d042 in __gmp_doprnt_integer (funs=0x555555583d80
<__gmp_asprintf_funs_noformat>, data=0x7fffffffe2e0, p=0x7fffffffe340,
s=0x7ffeff624010 "") at doprnti.c:125
#3 0x0000555555556ad0 in __gmp_doprnt_integer_ostream (o=...,
p=0x7fffffffe340, s=0x7ffeff624010 "") at osdoprnti.cc:60
#4 0x0000555555556a09 in operator<< (o=..., z=0x7fffffffe3d0) at
osmpz.cc:46
#5 0x0000555555556934 in operator<< <__mpz_struct [1], __mpz_struct [1]>
(o=..., expr=...) at ./gmpxx.h:2181
#6 0x0000555555556428 in main (argc=2, argv=0x7fffffffe528) at bigg.c:16
It appears that the character-size of strings at some layer
(__gmp_doprnt_integer?) is restricted to INT_MAX bytes of output.
Using int for the length in that file is certainly a bad sign. Generally,
formatted I/O hits limitations in GMP, see for instance
https://gmplib.org/list-archives/gmp-bugs/2015-November/003795.html and
various other reports. It may be possible to fix some of the printing
functions without any ABI break, but not others...
--
Marc Glisse
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