Re: [Libguestfs] nbdkit build failure (was: Re: jplesnik's nbdkit-1.35.5-4.fc39 failed to build)

On Thu, Jul 13, 2023 at 10:29:44AM +0100, Richard W.M. Jones wrote: > It's a crash in Perl code, although called from the nbdkit perl plugin > (C bindings). Still debugging this ... > > Core was generated by `/home/rjones/d/nbdkit/server/nbdkit -U /tmp/nbdkittPN34a/sock -P /tmp/nbdkittPN'. > Program terminated with signal SIGSEGV, Segmentation fault. > > warning: Section `.reg-xstate/150177' in core file too small. > #0 Perl_my_snprintf (buffer=0x7f3a1e5fc630 "p\310_\036:\177", len=32, > format=0x7f3a1ef7e322 "_<(eval %lu)") > at /usr/src/debug/perl-5.38.0-499.fc39.x86_64/util.c:5248 > Downloading source file /usr/src/debug/perl-5.38.0-499.fc39.x86_64/util.c > 5248 WITH_LC_NUMERIC_SET_TO_NEEDED( > [Current thread is 1 (Thread 0x7f3a1e5fd6c0 (LWP 150177))] > (gdb) bt > #0 Perl_my_snprintf (buffer=0x7f3a1e5fc630 "p\310_\036:\177", len=32, > format=0x7f3a1ef7e322 "_<(eval %lu)") > at /usr/src/debug/perl-5.38.0-499.fc39.x86_64/util.c:5248 https://github.com/Perl/perl5/blob/ff7e37d5ca2e55a1e53e5b375e3cc9aedc9ce4... Since its hardly obvious from the code, that macro expands to the monster below. I didn't bother to format it completely ... # 5245 "util.c" if (retval == -1) { do { void (*_restore_LC_NUMERIC_function)(PerlInterpreter* my_perl __attribute__((unused))) = ((void *)0); do { _Bool _in_lc_numeric = ((( (( _Bool ) ((my_perl->Icompiling).cop_hints & 0x00000004)) || ( ((_Bool) ((my_perl->Icompiling).cop_hints & 0x00000010)) && Perl__is_in_locale_category(my_perl, (1), ( 1 )))) || (((my_perl->Icurcop) && (((my_perl->Icurcop))->cop_hints + 0) & 0x00000004) || (((my_perl->Icurcop) && (((my_perl->Icurcop))->cop_hints + 0) & 0x00000010) && Perl__is_in_locale_category(my_perl, (0), ( 1 )))))); ((void)0); if (_in_lc_numeric) { if ((! (my_perl->Inumeric_underlying) && (my_perl->Inumeric_standard) < 2)) { Perl_set_numeric_underlying(my_perl); _restore_LC_NUMERIC_function = &Perl_set_numeric_standard; } } else { if ((! (my_perl->Inumeric_standard))) { Perl_set_numeric_standard(my_perl); _restore_LC_NUMERIC_function = &Perl_set_numeric_underlying; } } } while (0); retval = vsnprintf(buffer, len, format, ap);; do { if (_restore_LC_NUMERIC_function) { _restore_LC_NUMERIC_function(my_perl); } ((void)0); } while (0); } while (0); ... because the fundamental problem is: (gdb) print my_perl $13 = (PerlInterpreter *) 0x0 so that's not gonna work.