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[perl #97988] readline can cause PL_last_in_gv to point to freed scalar

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From:
Father Chrysostomos
Date:
August 28, 2011 22:32
Subject:
[perl #97988] readline can cause PL_last_in_gv to point to freed scalar
Message ID:
rt-3.6.HEAD-31297-1314595965-1076.97988-75-0@perl.org
# New Ticket Created by  Father Chrysostomos 
# Please include the string:  [perl #97988]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=97988 >


With a custom-modified perl that has an sv_dump statement in pp_tell:

$ ./miniperl -e '$f{g} = *foo; readline $f{g}; $f{g} = 3; undef %f; tell'
SV = UNKNOWN(0xff) (0x803ad0) at 0x803a00
REFCNT = 0
FLAGS = ()

I haven’t come up with a crashing case yet.

Is there any reason pp_readline can’t use ck_fun? I think that would solve this.

---
Flags:
category=core
severity=low
---
Site configuration information for perl 5.15.2:

Configured by sprout at Wed Aug 24 09:37:32 PDT 2011.

Summary of my perl5 (revision 5 version 15 subversion 2) configuration:
Derived from: 39984ce57c0ac2c090eb39bdd7c344202a85043d
Ancestor: 7bc95ae1a56bd0ccfe9db1092344cd2d1566beca
Platform:
osname=darwin, osvers=10.5.0, archname=darwin-thread-multi-2level
uname='darwin pint.local 10.5.0 darwin kernel version 10.5.0: fri nov 5 23:20:39 pdt 2010; root:xnu-1504.9.17~1release_i386 i386 '
config_args='-de -Dusedevel -DDEBUGGING -Duseithreads'
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='cc', ccflags ='-fno-common -DPERL_DARWIN -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
optimize='-O3 -g',
cppflags='-fno-common -DPERL_DARWIN -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib
libs=-ldbm -ldl -lm -lutil -lc
perllibs=-ldl -lm -lutil -lc
libc=, so=dylib, useshrplib=false, libperl=libperl.a
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector'

Locally applied patches:


---
@INC for perl 5.15.2:
lib
/usr/local/lib/perl5/site_perl/5.15.2/darwin-thread-multi-2level
/usr/local/lib/perl5/site_perl/5.15.2
/usr/local/lib/perl5/5.15.2/darwin-thread-multi-2level
/usr/local/lib/perl5/5.15.2
/usr/local/lib/perl5/site_perl
.

---
Environment for perl 5.15.2:
DYLD_LIBRARY_PATH (unset)
HOME=/Users/sprout
LANG=en_US.UTF-8
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/bin
PERL_BADLANG (unset)
SHELL=/bin/bash


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