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[perl #77934] Bus error with (unshared) dir handles and threads

From:
Father Chrysostomos
Date:
September 19, 2010 18:23
Subject:
[perl #77934] Bus error with (unshared) dir handles and threads
Message ID:
rt-3.6.HEAD-5116-1284945817-112.77934-75-0@perl.org
# New Ticket Created by  Father Chrysostomos 
# Please include the string:  [perl #77934]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=77934 >


I was wondering whether readdir is thread-safe, so I wrote this script:

#!perl -l

chdir '/tmp';
mkdir "toberead$$";
chdir "toberead$$";
open thing, ">$_" and close thing or die "$_: $!" for a..z;

use threads;
$thr = async {
 opendir dir, ".";
 $start = telldir dir;
 readdir dir or seekdir dir, 0 while 1;
} if $ARGV[0];

opendir dir, ".";
for(1..26) {
 print scalar readdir dir;
 select undef, undef, undef, .25;
}

$thr->kill(KILL) if $ARGV[0];
__END__

Pass an argument to it to start the other thread.

What surprised me was that the output is all correct (. .. a b c ... v w x), but then there is a bus error.

My patch for 75154 (cloning dir handles) doesn’t fix it, so this is a separate bug.

---
Flags:
    category=core
    severity=low
---
Site configuration information for perl 5.13.4:

Configured by sprout at Mon Sep 13 22:18:01 PDT 2010.

Summary of my perl5 (revision 5 version 13 subversion 4 patch v5.13.4-224-g25222ff) configuration:
  Snapshot of: 25222ff958727e01a3a480924b65ba188c7c3ea2
  Platform:
    osname=darwin, osvers=10.4.0, archname=darwin-2level
    uname='darwin pint.local 10.4.0 darwin kernel version 10.4.0: fri apr 23 18:28:53 pdt 2010; root:xnu-1504.7.4~1release_i386 i386 '
    config_args='-de -Dusedevel -DDEBUGGING'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    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 -no-cpp-precomp -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
    optimize='-O3 -g',
    cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN -no-cpp-precomp -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=/usr/lib/libc.dylib, 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 5.13.4:
    /usr/local/lib/perl5/site_perl/5.13.4/darwin-2level
    /usr/local/lib/perl5/site_perl/5.13.4
    /usr/local/lib/perl5/5.13.4/darwin-2level
    /usr/local/lib/perl5/5.13.4
    /usr/local/lib/perl5/site_perl
    .

---
Environment for perl 5.13.4:
    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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