perlbug-followup at perl
Apr 10, 2008, 11:13 PM
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[perl #52740] crash when localizing a symtab entry
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# New Ticket Created by Niko Tyni
# Please include the string: [perl #52740]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=52740 >
This snippet crashes Perl 5.10.0 and blead (as of change 33541 which
is the last one in the utsl.gen.nz git repository) with a segmentation fault:
use Compress::Zlib;
use Devel::Symdump;
print Devel::Symdump->isa_tree;
__END__
(The snippet is reduced from the mod_perl2 2.0.4rc1 test suite,
where Apache crashes on shutdown after the tests.)
This can be reduced to
use constant "foo" => "a";
index("a", foo);
local(*g) = ${::}{foo};
__END__
and expanded to this core-only test:
BEGIN {
$|=1;
print "1..2\n";
my $name = "foo";
my $scalar = "a";
if ($] > 5.009002) {
my $symtab = \%{'::'};
$symtab->{$name} = \$scalar;
} else {
*{"::$name"} = sub () { $scalar };
}
}
print "ok 1\n" if index("a", foo) >= 0;
local(*g) = ${::}{foo};
END {print "ok 2\n";}
__END__
Bisecting shows the segfault started with
[ 29544] By: nicholas on 2006/12/13 08:35:43
Log: Eliminate PVBM. Store fast Boyer-Moore tables in PVGV.
Add the placeholder for new type, temporarily named BIND, for binding
and aliasing in 6 on 5.
Branch: perl
! dump.c ext/B/B.xs ext/Storable/Storable.xs op.h
! pod/perltodo.pod pp_hot.c sv.c sv.h util.c
On blead, change 32708 turns this into an assertion failure with -DDEBUGGING:
miniperl: sv.c:3231: S_glob_assign_glob: Assertion `((((shplep)->sv_flags & (0x00004000|0x00008000)) == 0x00008000) && (((svtype)((shplep)->sv_flags & 0xff)) == SVt_PVGV || ((svtype)((shplep)->sv_flags & 0xff)) == SVt_PVLV))' failed.
../testscript: line 3: 3158 Aborted (core dumped) ./miniperl ${HOME}/t.pl
Backtrace of 'miniperl' as of change 33541 without -DDEBUGGING:
Core was generated by `./miniperl /home/niko/t.pl'.
Program terminated with signal 11, Segmentation fault.
[New process 23428]
#0 0x0000000000488f67 in S_unshare_hek_or_pvn (my_perl=0x7c7010, hek=0x31, str=0x0, len=0, hash=0)
at hv.c:2294
2294 if (he->shared_he_he.he_valu.hent_refcount - 1) {
(gdb) bt
#0 0x0000000000488f67 in S_unshare_hek_or_pvn (my_perl=0x7c7010, hek=0x31, str=0x0, len=0, hash=0)
at hv.c:2294
#1 0x0000000000488f18 in Perl_unshare_hek (my_perl=0x7c7010, hek=0x31) at hv.c:2263
#2 0x000000000040a776 in Perl_gp_free (my_perl=0x7c7010, gv=0x7e8820) at gv.c:1583
#3 0x00000000004ed305 in Perl_leave_scope (my_perl=0x7c7010, base=0) at scope.c:821
#4 0x00000000004ea2cd in Perl_pop_scope (my_perl=0x7c7010) at scope.c:102
#5 0x00000000004a48a6 in Perl_pp_leave (my_perl=0x7c7010) at pp_hot.c:1882
#6 0x000000000049b9d3 in Perl_runops_standard (my_perl=0x7c7010) at run.c:38
#7 0x0000000000494971 in S_run_body (my_perl=0x7c7010, oldscope=1) at perl.c:2400
#8 0x000000000049437e in perl_run (my_perl=0x7c7010) at perl.c:2320
#9 0x000000000057375e in main (argc=2, argv=0x7fff820a3c88, env=0x7fff820a3ca0) at miniperlmain.c:113
Backtrace with -DDEBUGGING and the assertion failure above:
Core was generated by `./miniperl /home/niko/t.pl'.
Program terminated with signal 6, Aborted.
[New process 14219]
#0 0x00002b50c8c431d5 in raise () from /lib/libc.so.6
(gdb) bt
#0 0x00002b50c8c431d5 in raise () from /lib/libc.so.6
#1 0x00002b50c8c44680 in abort () from /lib/libc.so.6
#2 0x00002b50c8c3c75f in __assert_fail () from /lib/libc.so.6
#3 0x000000000053affd in S_glob_assign_glob (my_perl=0x984010, dstr=0x9a70d8, sstr=0x9a70a8, dtype=9)
at sv.c:3366
#4 0x0000000000540f07 in Perl_sv_setsv_flags (my_perl=0x984010, dstr=0x9a70d8, sstr=0x9a70a8,
flags=1538) at sv.c:3717
#5 0x000000000050cc8a in Perl_pp_aassign (my_perl=0x984010) at pp_hot.c:1074
#6 0x00000000004ad3dc in Perl_runops_debug (my_perl=0x984010) at dump.c:1984
#7 0x00000000004f6ae3 in S_run_body (my_perl=0x984010, oldscope=1) at perl.c:2400
#8 0x00000000004f5e15 in perl_run (my_perl=0x984010) at perl.c:2320
#9 0x00000000006b087e in main (argc=2, argv=0x7fffe2987578, env=0x7fffe2987590) at miniperlmain.c:113
---
Flags:
category=core
severity=medium
---
Site configuration information for perl 5.10.0:
Configured by Debian Project at Sun Mar 30 20:28:28 UTC 2008.
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
Platform:
osname=linux, osvers=2.6.18-6-xen-amd64, archname=x86_64-linux-gnu-thread-multi
uname='linux sid 2.6.18-6-xen-amd64 #1 smp sun feb 10 18:02:52 utc 2008 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/5.10.0 -Dsitearch=/usr/local/lib/perl/5.10.0 -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.5.10.0 -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 -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 -I/usr/local/include'
ccversion='', gccversion='4.2.3 (Debian 4.2.3-3)', 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 =' -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-2.7.so, so=so, useshrplib=true, libperl=libperl.so.5.10.0
gnulibc_version='2.7'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib'
Locally applied patches:
---
@INC for perl 5.10.0:
/etc/perl
/usr/local/lib/perl/5.10.0
/usr/local/share/perl/5.10.0
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.10
/usr/share/perl/5.10
/usr/local/lib/site_perl
.
---
Environment for perl 5.10.0:
HOME=/root
LANG (unset)
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PERL_BADLANG (unset)
SHELL=/bin/bash
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