From tobyink@cpan.org

This is a bug report for perl from tobyink@​cpan.org,
generated with the help of perlbug 1.39 running under perl 5.10.1.

The following code segfaults in 5.10.1 and 5.14.2 (and presumably
everything in between) on Linux and probably other platforms​:

use 5.010;
my $a = [qw/a A/];
my $b = ['b', $a, 'B'];
push @​$a, $b;
say 'hurrah' if 'B' ~~ $b;

While this kind of error probably should indeed die (it doesn't
make sense to use a cyclical structure for smart matching), it
shouldn't be a segfault but rather an error that can be caught by
'eval'.

This could probably be fixed by having the smart match operator
maintain a list of references it has "visited" and refuse to revisit
a previously visited reference.

(In addition, my mail server seems to reject e-mails sent using the
perlbug program, claiming they don't contain valid Date and From
headers. So I'm sending this message through my e-mail client instead.)

Flags​:
  category=core
  severity=high

Site configuration information for perl 5.10.1​:

Configured by Mandriva at Fri Jun 11 13​:12​:00 EDT 2010.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration​:
 
  Platform​:
  osname=linux, osvers=2.6.27.45-server-1mnb,
archname=i386-linux-thread-multi uname='linux titan.mandriva.com
2.6.27.45-server-1mnb #1 smp fri jan 29 15​:41​:43 est 2010 i686 intel(r)
xeon(r) cpu x3360 @​ 2.83ghz gnulinux ' config_args='-des
-Dinc_version_list=5.10.0 5.10.0/i386-linux-thread-multi 5.8.8 5.8.7
5.8.6 5.8.5 5.8.4 5.8.3 5.8.2 5.8.1 5.8.0 5.6.1 5.6.0
-Darchname=i386-linux -Dcc=i586-mandriva-linux-gnu-gcc -Doptimize=-O2
-g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-fexceptions -fstack-protector --param=ssp-buffer-size=4
-fomit-frame-pointer -march=i586 -mtune=generic
-fasynchronous-unwind-tables -DDEBUGGING=-g -Dprefix=/usr
-Dvendorprefix=/usr -Dsiteprefix=/usr -Dsitebin=/usr/local/bin
-Dsiteman1dir=/usr/local/share/man/man1
-Dsiteman3dir=/usr/local/share/man/man3 -Dman3ext=3pm -Dcf_by=Mandriva
-Dmyhostname=localhost -Dperladmin=root@​localhost
-Dcf_email=root@​localhost -Dd_dosuid -Ud_csh -Duseshrplib -Duseithreads
-Di_db -Di_ndbm -Di_gdbm' hint=recommended, useposix=true,
d_sigaction=define useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=undef, use64bitall=undef, uselongdouble=undef
usemymalloc=n, bincompat5005=undef Compiler​:
cc='i586-mandriva-linux-gnu-gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE
-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2 -g -pipe
-Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
-fstack-protector --param=ssp-buffer-size=4 -fomit-frame-pointer
-march=i586 -mtune=generic -fasynchronous-unwind-tables',
cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe
-fstack-protector -I/usr/local/include' ccversion='',
gccversion='4.4.1', gccosandvers='' intsize=4, longsize=4, ptrsize=4,
doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8,
d_longdbl=define, longdblsize=12 ivtype='long', ivsize=4,
nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=4,
prototype=define Linker and Libraries​:
ld='i586-mandriva-linux-gnu-gcc', ldflags =' -fstack-protector
-L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lnsl -lgdbm
-ldb -ldl -lm -lcrypt -lutil -lpthread -lc -lgdbm_compat perllibs=-lnsl
-ldl -lm -lcrypt -lutil -lpthread -lc libc=/lib/libc-2.10.1.so, so=so,
useshrplib=true, libperl=libperl.so gnulibc_version='2.10.1' Dynamic
Linking​: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef,
ccdlflags='-Wl,-E
-Wl,-rpath,/usr/lib/perl5/5.10.1/i386-linux-thread-multi/CORE'
cccdlflags='-fPIC', lddlflags='-shared -O2 -g -pipe -Wformat
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
-fstack-protector --param=ssp-buffer-size=4 -fomit-frame-pointer
-march=i586 -mtune=generic -fasynchronous-unwind-tables
-L/usr/local/lib'

Locally applied patches​:
  Mandriva Linux patches

@​INC for perl 5.10.1​:
  /usr/lib/perl5/site_perl/5.10.1/i386-linux-thread-multi
  /usr/lib/perl5/site_perl/5.10.1
  /usr/lib/perl5/vendor_perl/5.10.1/i386-linux-thread-multi
  /usr/lib/perl5/vendor_perl/5.10.1
  /usr/lib/perl5/5.10.1/i386-linux-thread-multi
  /usr/lib/perl5/5.10.1
  /usr/lib/perl5/site_perl
  /usr/lib/perl5/vendor_perl/5.10.0
  /usr/lib/perl5/vendor_perl/5.10.0/i386-linux-thread-multi
  /usr/lib/perl5/vendor_perl
  .

Environment for perl 5.10.1​:
  HOME=/home/tai
  LANG=en_GB.UTF-8
  LANGUAGE=en_GB.UTF-8​:en_GB​:en
  LC_ADDRESS=en_GB.UTF-8
  LC_COLLATE=en_GB.UTF-8
  LC_CTYPE=en_GB.UTF-8
  LC_IDENTIFICATION=en_GB.UTF-8
  LC_MEASUREMENT=en_GB.UTF-8
  LC_MESSAGES=en_GB.UTF-8
  LC_MONETARY=en_GB.UTF-8
  LC_NAME=en_GB.UTF-8
  LC_NUMERIC=en_GB.UTF-8
  LC_PAPER=en_GB.UTF-8
  LC_SOURCED=1
  LC_TELEPHONE=en_GB.UTF-8
  LC_TIME=en_GB.UTF-8
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/home/tai/perl5/perlbrew/bin​:/home/tai/bin​:/bin​:/usr/bin​:/usr/local/bin​:/usr/games​:/usr/lib/qt4/bin​:/home/tai/bin​:/opt/parrot/bin
  PERLBREW_PATH=/home/tai/perl5/perlbrew/bin
  PERLBREW_ROOT=/home/tai/perl5/perlbrew
  PERLBREW_VERSION=0.29
  PERL_BADLANG (unset)
  SHELL=/bin/tcsh

--
Toby A Inkster
<mailto​:mail@​tobyinkster.co.uk>
<http​://tobyinkster.co.uk>

From @jkeenan

On Mon Nov 21 02​:05​:57 2011, tobyink@​cpan.org wrote​:

The following code segfaults in 5.10.1 and 5.14.2 (and presumably
everything in between) on Linux and probably other platforms​:

use 5.010;
my $a = [qw/a A/];
my $b = ['b', $a, 'B'];
push @​$a, $b;
say 'hurrah' if 'B' ~~ $b;

Note that if we switch the positions of 'b' and 'B' in the second
arrayref, the program DWIMs​:

$ cat 104162.pl
use feature qw( :5.10 );
my $x = [qw/a A/];
my $y = ['B', $x, 'b'];
push @​$x, $y;
say 'hurrah' if 'B' ~~ $y;

$ perl 104162.pl
hurrah

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

From tobyink@cpan.org

On the newly released 5.16.0-RC0, the following still segfaults​:

perl -E'my $a = [qw/a A/]; my $b = ["b", $a, "B"]; push @​$a, $b; say
"hurrah" if 'B' ~~ $b;'

From [Unknown Contact. See original ticket]

On the newly released 5.16.0-RC0, the following still segfaults​:

perl -E'my $a = [qw/a A/]; my $b = ["b", $a, "B"]; push @​$a, $b; say
"hurrah" if 'B' ~~ $b;'