[perl #70862] perl -e 'eval { $::{"@"}="" }' => Segmentation fault
Frank Wiegand
# Please include the string: [perl #70862]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=70862 >
This is a bug report for perl from frank....@gmail.com,
generated with the help of perlbug 1.39 running under perl 5.10.1.
-----------------------------------------------------------------
% perl -e 'eval { $::{"@"}="" }'
zsh: segmentation fault perl -e 'eval { $::{"@"}="" }'
This is still broken in 5.11.2.
git bisect says:
commit e654831bf5852e58816193ed94d40e2031346fa6
Author: Nicholas Clark <ni...@ccl4.org>
Date: Sat Jan 28 14:02:10 2006 +0000
PERL_DONT_CREATE_GVSV wasn't as effective as it should have been.
p4raw-id: //depot/perl@26980
Bye, Frank
-----------------------------------------------------------------
---
Flags:
category=core
severity=low
---
Site configuration information for perl 5.10.1:
Configured by Debian Project at Sat Nov 7 22:18:45 UTC 2009.
Summary of my perl5 (revision 5 version 10 subversion 1) configuration:
Platform:
osname=linux, osvers=2.6.31.5-dsa-amd64, archname=x86_64-linux-gnu-thread-multi
uname='linux brahms 2.6.31.5-dsa-amd64 #1 smp fri oct 23 12:25:24 cest 2009 x86_64 gnulinux '
config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.10.1 -Dsitearch=/usr/local/lib/perl/5.10.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.10.1 -Dd_dosuid -des'
hint=recommended, useposix=true, d_sigaction=define
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=define, use64bitall=define, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O2 -g',
cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
ccversion='', gccversion='4.3.4', gccosandvers=''
intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib /lib64 /usr/lib64
libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
perllibs=-ldl -lm -lpthread -lc -lcrypt
libc=/lib/libc-2.10.1.so, so=so, useshrplib=true, libperl=libperl.so.5.10.1
gnulibc_version='2.10.1'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector'
Locally applied patches:
---
@INC for perl 5.10.1:
/etc/perl
/usr/local/lib/perl/5.10.1
/usr/local/share/perl/5.10.1
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.10
/usr/share/perl/5.10
/usr/local/lib/site_perl
.
---
Environment for perl 5.10.1:
HOME=/home/fw
LANG=de_DE.UTF-8
LANGUAGE=
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/sbin:/usr/sbin:/home/fw/bin:/home/fw/bin:/usr/local/bin:/usr/bin:/bin:/usr/games
PERL_AUTOINSTALL=--defaultdeps
PERL_BADLANG (unset)
PERL_EXTUTILS_AUTOINSTALL=--defaultdeps
PERL_MM_USE_DEFAULT=1
SHELL=/bin/zsh
Abigail
> # New Ticket Created by Frank Wiegand
> # Please include the string: [perl #70862]
> # in the subject line of all future correspondence about this issue.
> # <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=70862 >
>
>
> This is a bug report for perl from frank....@gmail.com,
> generated with the help of perlbug 1.39 running under perl 5.10.1.
>
>
> -----------------------------------------------------------------
>
> % perl -e 'eval { $::{"@"}="" }'
> zsh: segmentation fault perl -e 'eval { $::{"@"}="" }'
>
> This is still broken in 5.11.2.
>
> git bisect says:
>
> commit e654831bf5852e58816193ed94d40e2031346fa6
> Author: Nicholas Clark <ni...@ccl4.org>
> Date: Sat Jan 28 14:02:10 2006 +0000
>
> PERL_DONT_CREATE_GVSV wasn't as effective as it should have been.
>
> p4raw-id: //depot/perl@26980
>
>
> Bye, Frank
>
It gives me (5.10.1):
$ perl -e 'eval { $::{"@"}="" }'
Assertion sv failed: file "sv.c", line 4097 at -e line 1.
Abigail
Eric Brine
> It gives me (5.10.1):
>
> $ perl -e 'eval { $::{"@"}="" }'
> Assertion sv failed: file "sv.c", line 4097 at -e line 1.
>
And blead:
$ perl -e 'eval { $::{"@"}="" }'
perl: sv.c:4315: Perl_sv_setpvn: Assertion `sv' failed.
Aborted
The call originates in CLEAR_ERRSV(); in pp_leavetry
Nicholas Clark
This will also trigger the same assertion, but with a different call stack:
$ perl -e '$::{"@"}=""; eval {}'
This is more fun:
$ perl -e 'eval { $::{"@"}=\3 }'
Modification of a read-only value attempted at -e line 1.
This blows the C stack with infinite recursion:
perl -e '$::{"@"}=\3; eval {}'
I'm not certain what the right fix for the original bug is. I'm really not
sure about the problems with using \3
Nicholas Clark
Ben Morrow
> On Fri, Nov 27, 2009 at 01:11:26PM -0500, Eric Brine wrote:
> > On Fri, Nov 27, 2009 at 7:42 AM, Abigail <abi...@abigail.be> wrote:
> >
> > > It gives me (5.10.1):
> > >
> > > $ perl -e 'eval { $::{"@"}="" }'
> > > Assertion sv failed: file "sv.c", line 4097 at -e line 1.
> > >
> >
> > And blead:
> > $ perl -e 'eval { $::{"@"}="" }'
> > perl: sv.c:4315: Perl_sv_setpvn: Assertion `sv' failed.
> > Aborted
> >
> > The call originates in CLEAR_ERRSV(); in pp_leavetry
>
> This will also trigger the same assertion, but with a different call stack:
>
> $ perl -e '$::{"@"}=""; eval {}'
Is there really any good reason not to just say 'don't be so damn
stupid'? What possible use is there for modifying the symbol table entry
of a magic variable?
One fix might be to forbid the assignment altogether.
Ben
Aristotle Pagaltzis
> Is there really any good reason not to just say 'don't be so
> damn stupid'?
The interpreter shouldn’t just up and crash. No matter what.
> What possible use is there for modifying the symbol table
> entry of a magic variable?
Probably none. That’s a different question from your first one.
> One fix might be to forbid the assignment altogether.
An orderly exception would be just fine, just so long as the
interpreter doesn’t summarily kick the bucket.
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
Nicholas Clark
> On Fri, Nov 27, 2009 at 01:11:26PM -0500, Eric Brine wrote:
> > On Fri, Nov 27, 2009 at 7:42 AM, Abigail <abi...@abigail.be> wrote:
> >
> > > It gives me (5.10.1):
> > >
> > > $ perl -e 'eval { $::{"@"}="" }'
> > > Assertion sv failed: file "sv.c", line 4097 at -e line 1.
> > >
> >
> > And blead:
> > $ perl -e 'eval { $::{"@"}="" }'
> > perl: sv.c:4315: Perl_sv_setpvn: Assertion `sv' failed.
> > Aborted
> >
> > The call originates in CLEAR_ERRSV(); in pp_leavetry
>
> This will also trigger the same assertion, but with a different call stack:
>
> $ perl -e '$::{"@"}=""; eval {}'
Should be fixed by f5fa9033b8c1fdcbd7710850b3b0380d6b937853.
> This is more fun:
>
> $ perl -e 'eval { $::{"@"}=\3 }'
> Modification of a read-only value attempted at -e line 1.
>
> This blows the C stack with infinite recursion:
>
> perl -e '$::{"@"}=\3; eval {}'
>
> I'm not certain what the right fix for the original bug is. I'm really not
> sure about the problems with using \3
Fixed with dfd167e94af611f6248e804cb228b35ca4123bd6
Nicholas Clark