From @leahneukirchen

Created by @leahneukirchen

(Please note that this bug report applies to perl 5.26.0 on
a Linux 4.12 x86_64 system with musl libc 1.1.6.)

Perl 5.26.0 uses memmem in fbm_instr via ninstr if available,
but this function can be defined only when a feature flag like
_GNU_SOURCE is set.

Currently, perl detects memmem on musl (because the symbol is there),
but doesn't define _GNU_SOURCE, so no prototype is declared and the
return value is assumed to be an int, thus line 951 of util.c
will truncate the pointer into a 32-bit value, and
little_p - big_p in pp_index is suddenly very big. ;)

This resulted in the following script

my $fn = 'Class/Inspector.pm';
print index('lib/Class/Inspector.pm', $fn);
print "\n";
print index('lib/Class/Inspector.pm', 'Class/Inspector.pm');

printing

% perl /tmp/foo.pl
-94012539142140
4

Forcing the use of _GNU_SOURCE (as seen below in ccflags) fixes the issue,
perhaps there is a better test.

Flags:
    category=core
    severity=medium

Site configuration information for perl 5.26.0:

Summary of my perl5 (revision 5 version 26 subversion 0) configuration:
   
  Platform:
    osname=linux
    osvers=current
    archname=x86_64-linux
    uname=''
    config_args='--prefix=/usr -Dusethreads -Duseshrplib -Dusesoname -Dusevendorprefix -Dprefix=/usr -Dvendorprefix=/usr -Dprivlib=/usr/share/perl5/core_perl -Darchlib=/usr/lib/perl5/core_perl -Dsitelib=/usr/share/perl5/site_perl -Dsitearch=/usr/lib/perl5/site_perl -Dvendorlib=/usr/share/perl5/vendor_perl -Dvendorarch=/usr/lib/perl5/vendor_perl -Dscriptdir=/usr/bin -Dvendorscript=/usr/bin -Dinc_version_list=none -Dman1ext=1p -Dman3ext=3p -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dd_sockaddr_in6=define -Dcccdlflags=-fPIC -Doptimize= -Wall  -Wl,-z,relro -Wl,-z,now -Wl,--as-needed	-Dperl_static_inline=static __inline__ -Dd_static_inline'
    hint=default
    useposix=true
    d_sigaction=define
    useithreads=define
    usemultiplicity=undef
    use64bitint=undef
    use64bitall=undef
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=undef
    bincompat5005=undef
  Compiler:
    cc='cc'
    ccflags ='	 -fstack-protector-strong -D_FORTIFY_SOURCE=2 -mtune=generic -O2 -pipe	  -D_GNU_SOURCE '
    optimize=' -Wall   -fstack-protector-strong -D_FORTIFY_SOURCE=2 -mtune=generic -O2 -pipe	-D_GNU_SOURCE '
    cppflags=''
    ccversion=''
    gccversion='0.0'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=0
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags =' -Wl,-z,relro -Wl,-z,now -Wl,--as-needed	  '
    libpth=/lib /usr/lib /usr/local/lib
    libs=-lm -lcrypt -lpthread -lgdbm -ldb -ldl -lgdbm_compat
    perllibs=-lm -lcrypt -lpthread -ldl
    libc=
    so=so
    useshrplib=true
    libperl=libperl.so.5.26.0
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E'
    cccdlflags='-fPIC'
    lddlflags='-shared	-Wl,-z,relro -Wl,-z,now -Wl,--as-needed    '



@INC for perl 5.26.0:
    /usr/lib/perl5/site_perl
    /usr/share/perl5/site_perl
    /usr/lib/perl5/vendor_perl
    /usr/share/perl5/vendor_perl
    /usr/lib/perl5/core_perl
    /usr/share/perl5/core_perl


Environment for perl 5.26.0:
    HOME=/tmp
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LC_COLLATE=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/void-packages:/usr/bin:/usr/sbin
    PERL_BADLANG (unset)
    SHELL=/bin/sh

From @jkeenan

On Tue, 19 Sep 2017 17​:37​:54 GMT, leah@​vuxu.org wrote​:

This is a bug report for perl from leah@​vuxu.org,
generated with the help of perlbug 1.40 running under perl 5.26.0.

-----------------------------------------------------------------
[Please describe your issue here]

(Please note that this bug report applies to perl 5.26.0 on
a Linux 4.12 x86_64 system with musl libc 1.1.6.)

For reference​: https://en.wikipedia.org/wiki/Musl

Perl 5.26.0 uses memmem in fbm_instr via ninstr if available,
but this function can be defined only when a feature flag like
_GNU_SOURCE is set.

Currently, perl detects memmem on musl (because the symbol is there),
but doesn't define _GNU_SOURCE, so no prototype is declared and the
return value is assumed to be an int, thus line 951 of util.c
will truncate the pointer into a 32-bit value, and
little_p - big_p in pp_index is suddenly very big. ;)

This resulted in the following script

my $fn = 'Class/Inspector.pm';
print index('lib/Class/Inspector.pm', $fn);
print "\n";
print index('lib/Class/Inspector.pm', 'Class/Inspector.pm');

printing

% perl /tmp/foo.pl
-94012539142140
4

Forcing the use of _GNU_SOURCE (as seen below in ccflags) fixes the
issue,
perhaps there is a better test.

Also for reference​: locations in the core distribution which mention _GNU_SOURCE​:

$ ack -l _GNU_SOURCE . |sort
config_h.SH
cpan/Config-Perl-V/t/21_plv58.t
cpan/Config-Perl-V/t/27_plv5200.t
cpan/Config-Perl-V/t/27_plv5202.t
cpan/Config-Perl-V/t/28_plv5220.t
cpan/Config-Perl-V/t/30_plv5240.t
cpan/Config-Perl-V/t/31_plv52511.t
cpan/Config-Perl-V/t/32_plv5261rc1.t
hints/cygwin.sh
hints/freemint.sh
hints/gnu.sh
hints/linux.sh
NetWare/config_H.wc
plan9/config_h.sample
plan9/config.plan9
Porting/config_H
uconfig.h
win32/config_H.ce
win32/config_H.gc
win32/config_H.vc

Can someone familiar with ccflags take a look at this ticket? Could the OP's concern be accommodated somewhere in a hints file?

Thank you very much.
--
James E Keenan (jkeenan@​cpan.org)

The RT System itself - Status changed from 'new' to 'open'

From @jkeenan

On Tue, 19 Sep 2017 17​:37​:54 GMT, leah@​vuxu.org wrote​:

This is a bug report for perl from leah@​vuxu.org,
generated with the help of perlbug 1.40 running under perl 5.26.0.

-----------------------------------------------------------------
[Please describe your issue here]

(Please note that this bug report applies to perl 5.26.0 on
a Linux 4.12 x86_64 system with musl libc 1.1.6.)

Perl 5.26.0 uses memmem in fbm_instr via ninstr if available,
but this function can be defined only when a feature flag like
_GNU_SOURCE is set.

Currently, perl detects memmem on musl (because the symbol is there),
but doesn't define _GNU_SOURCE, so no prototype is declared and the
return value is assumed to be an int, thus line 951 of util.c
will truncate the pointer into a 32-bit value, and
little_p - big_p in pp_index is suddenly very big. ;)

This resulted in the following script

my $fn = 'Class/Inspector.pm';
print index('lib/Class/Inspector.pm', $fn);
print "\n";
print index('lib/Class/Inspector.pm', 'Class/Inspector.pm');

printing

% perl /tmp/foo.pl
-94012539142140
4

Forcing the use of _GNU_SOURCE (as seen below in ccflags) fixes the
issue,
perhaps there is a better test.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags​:
category=core
severity=medium
---
Site configuration information for perl 5.26.0​:

Summary of my perl5 (revision 5 version 26 subversion 0)
configuration​:

Platform​:
osname=linux
osvers=current
archname=x86_64-linux
uname=''
config_args='--prefix=/usr -Dusethreads -Duseshrplib -Dusesoname
-Dusevendorprefix -Dprefix=/usr -Dvendorprefix=/usr
-Dprivlib=/usr/share/perl5/core_perl
-Darchlib=/usr/lib/perl5/core_perl
-Dsitelib=/usr/share/perl5/site_perl
-Dsitearch=/usr/lib/perl5/site_perl
-Dvendorlib=/usr/share/perl5/vendor_perl
-Dvendorarch=/usr/lib/perl5/vendor_perl -Dscriptdir=/usr/bin
-Dvendorscript=/usr/bin -Dinc_version_list=none -Dman1ext=1p
-Dman3ext=3p -Dman1dir=/usr/share/man/man1
-Dman3dir=/usr/share/man/man3 -Dd_sockaddr_in6=define -Dcccdlflags=-
fPIC -Doptimize= -Wall -Wl,-z,relro -Wl,-z,now -Wl,--as-needed
-Dperl_static_inline=static __inline__ -Dd_static_inline'
hint=default
useposix=true
d_sigaction=define
useithreads=define
usemultiplicity=undef
use64bitint=undef
use64bitall=undef
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=undef
bincompat5005=undef
Compiler​:
cc='cc'
ccflags =' -fstack-protector-strong -D_FORTIFY_SOURCE=2
-mtune=generic -O2 -pipe -D_GNU_SOURCE '
optimize=' -Wall -fstack-protector-strong -D_FORTIFY_SOURCE=2
-mtune=generic -O2 -pipe -D_GNU_SOURCE '
cppflags=''
ccversion=''
gccversion='0.0'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=0
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries​:
ld='cc'
ldflags =' -Wl,-z,relro -Wl,-z,now -Wl,--as-needed '
libpth=/lib /usr/lib /usr/local/lib
libs=-lm -lcrypt -lpthread -lgdbm -ldb -ldl -lgdbm_compat
perllibs=-lm -lcrypt -lpthread -ldl
libc=
so=so
useshrplib=true
libperl=libperl.so.5.26.0
gnulibc_version=''
Dynamic Linking​:
dlsrc=dl_dlopen.xs
dlext=so
d_dlsymun=undef
ccdlflags='-Wl,-E'
cccdlflags='-fPIC'
lddlflags='-shared -Wl,-z,relro -Wl,-z,now -Wl,--as-needed '

---
@​INC for perl 5.26.0​:
/usr/lib/perl5/site_perl
/usr/share/perl5/site_perl
/usr/lib/perl5/vendor_perl
/usr/share/perl5/vendor_perl
/usr/lib/perl5/core_perl
/usr/share/perl5/core_perl

---
Environment for perl 5.26.0​:
HOME=/tmp
LANG=en_US.UTF-8
LANGUAGE (unset)
LC_COLLATE=C
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/void-packages​:/usr/bin​:/usr/sbin
PERL_BADLANG (unset)
SHELL=/bin/sh

Let's suppose that you are currently invoking ./Configure like this​:

#####
sh ./Configure -Dalpha -Dbeta -Dgamma
#####

... where you substitute the list of config_args you are currently using for alpha..beta..gamma.

Do you get any better results if you tack on two arguments at the end?

#####
sh ./Configure -Dalpha -Dbeta -Dgamma -Aoptimize="-D_GNU_SOURCE" -Accflags="-D_GNU_SOURCE"
#####

(Caution​: This is just a guess based on reading INSTALL.)

Thank you very much.
Jim Keenan
--
James E Keenan (jkeenan@​cpan.org)