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$SIG{__DIE__} + goto -> infinite recursion & segfault #14990

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p5pRT opened this issue Oct 16, 2015 · 3 comments
Open

$SIG{__DIE__} + goto -> infinite recursion & segfault #14990

p5pRT opened this issue Oct 16, 2015 · 3 comments
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distro-Linux type-core

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@p5pRT
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p5pRT commented Oct 16, 2015

Migrated from rt.perl.org#126376 (status was 'open')

Searchable as RT126376$
@p5pRT
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p5pRT commented Oct 16, 2015

From @FGasper

Created by @FGasper

----------------------------------------------------------------------
#!/usr/bin/perl

use strict;
use warnings;

syswrite \*STDOUT, "start!\n";

$SIG{'__DIE__'} = sub {
  goto \&_rethrow;
};

sub _rethrow {
  syswrite \*STDOUT, "rethrow​: @​_";
  die @​_;
}

die 'mayhem!';
----------------------------------------------------------------------

^^ Run the above code, and watch it segfault. It happens on all
perls from 5.8 to 5.22.

This should not (?) happen per "perldoc perlvar", which says
that $SIG{__DIE__} is disabled within a __DIE__ handler. The goto()
appears to be throwing that off, though.

Perl Info 

Flags:
    category=core
    severity=medium

This perlbug was built using Perl 5.10.1 in the Fedora build system.
It is being executed now by Perl 5.10.1 - Sun Nov  6 00:37:43 GMT 2011.

Site configuration information for perl 5.10.1:

Configured by Red Hat, Inc. at Sun Nov  6 00:37:43 GMT 2011.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration:
   
  Platform:
    osname=linux, osvers=2.6.32-44.2.el6.x86_64, archname=x86_64-linux-thread-multi
    uname='linux c6b5.bsys.dev.centos.org 2.6.32-44.2.el6.x86_64 #1 smp wed jul 21 12:48:32 edt 2010 x86_64 x86_64 x86_64 gnulinux '
    config_args='-des -Doptimize=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -DDEBUGGING=-g -Dversion=5.10.1 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dprefix=/usr -Dvendorprefix=/usr -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl5 -Dsitearch=/usr/local/lib64/perl5 -Dprivlib=/usr/share/perl5 -Darchlib=/usr/lib64/perl5 -Dvendorlib=/usr/share/perl5/vendor_perl -Dvendorarch=/usr/lib64/perl5/vendor_perl -Dinc_version_list=5.10.0 -Darchname=x86_64-linux-thread-multi -Dlibpth=/usr/local/lib64 /lib64 /usr/lib64 -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosuid -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl=n -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -Ud_sethostent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_endservent_r_proto -Ud_setservent_r_proto -Dscriptdir=/usr/bin'
    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='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 -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.4.5 20110214 (Red Hat 4.4.5-6)', 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='gcc', ldflags =' -fstack-protector'
    libpth=/usr/local/lib64 /lib64 /usr/lib64
    libs=-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.12'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E -Wl,-rpath,/usr/lib64/perl5/CORE'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic'

Locally applied patches:
    


@INC for perl 5.10.1:
    /home/fgasper/perl5/lib/perl5
    /home/fgasper/perl5/lib/perl5/x86_64-linux-thread-multi
    /home/fgasper/perl/home/fgasper/perl5/lib/perl5/x86_64-linux-thread-multi
    /home/fgasper/perl/home/fgasper/perl5/lib/perl5
    /home/fgasper/perl/usr/local/lib64/perl5
    /home/fgasper/perl/usr/local/share/perl5
    /home/fgasper/perl/usr/lib64/perl5/vendor_perl
    /home/fgasper/perl/usr/share/perl5/vendor_perl
    /home/fgasper/perl/usr/lib64/perl5
    /home/fgasper/perl/usr/share/perl5
    /home/fgasper/perl5/lib/perl5/x86_64-linux-thread-multi
    /home/fgasper/perl5/lib/perl5
    /usr/local/lib64/perl5
    /usr/local/share/perl5
    /usr/lib64/perl5/vendor_perl
    /usr/share/perl5/vendor_perl
    /usr/lib64/perl5
    /usr/share/perl5
    .


Environment for perl 5.10.1:
    HOME=/home/fgasper
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/fgasper/perl5/bin:/usr/local/jdk/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11R6/bin:/opt/dell/srvadmin/bin:/usr/local/cpanel/3rdparty/bin:/home/fgasper/bin
    PERL5LIB=/home/fgasper/perl5/lib/perl5
    PERL_BADLANG (unset)
    PERL_LOCAL_LIB_ROOT=/home/fgasper/perl5
    PERL_MB_OPT=--install_base "/home/fgasper/perl5"
    PERL_MM_OPT=INSTALL_BASE=/home/fgasper/perl5
    SHELL=/bin/bash

@p5pRT
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p5pRT commented Oct 21, 2015

From @tonycoz

On Fri Oct 16 12​:38​:18 2015, felipe@​felipegasper.com wrote​:

^^ Run the above code, and watch it segfault. It happens on all
perls from 5.8 to 5.22.

This should not (?) happen per "perldoc perlvar", which says
that $SIG{__DIE__} is disabled within a __DIE__ handler. The goto()
appears to be throwing that off, though.

goto &foo is one of the documented ways of exiting the __DIE__ handler, but it doesn't seem to be behaving as documented​:

  When a C<__DIE__> hook routine returns, the exception
processing continues as it would have in the absence of the hook,
unless the hook routine itself exits via a C<goto &sub>, a loop exit,
or a C<die()>.

The seg fault is due to running out of stack space from deep recursion.

As to the recursion, the code checks whether the CV for the __DIE__ handler is running (with CvDEPTH()), which it isn't after goto &_rethrow.

Tony

@p5pRT
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p5pRT commented Oct 21, 2015

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

@xenu xenu removed the affects-5.10 label Nov 19, 2021
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