map { while (1) } hangs perl during compilation

[p5pRT]

Migrated from rt.perl.org#1251 (status was 'resolved')

Searchable as RT1251$

[p5pRT]

From barries@slaysys.com

This​:

  sub foo {
  map {
  while (1) {} ;
  } @​wits_end ;
  }

  BEGIN {
  die ;
  }

Never dies. It sucks up all CPU instead.

This​:

  sub foo1 {
  map {
  ;
  } @​wits_end ;
  }

  sub foo2 {
  map {
  while ($i) {}
  } @​wits_end ;
  }

  die ;

dies nicely. Haven't checked under _60 (let alone _61).

"Do not go gently into that dark night...."

Perl Info

Site configuration information for perl 5.00503:

Configured by root at Fri May 28 10:03:51 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=linux, osvers=2.2.9, archname=i686-linux
    uname='linux jester.slaysys.com 2.2.9 #4 smp thu may 27 10:44:27 edt 1999 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
    cppflags='-Dbool=char -DHAS_BOOL'
    ccflags ='-Dbool=char -DHAS_BOOL'
    stdchar='char', d_stdstdio=undef, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
    libc=, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    


@INC for perl 5.00503:
    /home/barries/src/Safari/lib
    /usr/lib/perl5/5.00503/i686-linux
    /usr/lib/perl5/5.00503
    /usr/lib/perl5/site_perl/5.005/i686-linux
    /usr/lib/perl5/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/home/barries
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:~/bin:~/bin
    PERL5LIB=/home/barries/src/Safari/lib
    PERLDB_OPTS=AutoTrace
    PERL_BADLANG (unset)
    SHELL=/bin/bash

[p5pRT]

From [Unknown Contact. See original ticket]

On Sun, 22 Aug 1999 at 23​:38​:17 -0400, Barrie Slaymaker wrote​:

sub foo {
map {
while (1) {} ;
} @​wits_end ;
}

BEGIN {
die ;
}

Never dies. It sucks up all CPU instead.

A progress report​:

I took a peek with gdb, and it's stuck in Perl_ck_grep running round a
small circular list of items
  pp_nextstate->pp_stub->pp_unstack

We need to see where that came from... fold_constants getting confused?

Ian

[p5pRT]

From The RT System itself

map { while (1) {} } ();
BEGIN { die "ok 1" }

[p5pRT]

From @floatingatoll

[RT_System - Tue Aug 24 07​:29​:00 1999]​:

On Sun, 22 Aug 1999 at 23​:38​:17 -0400, Barrie Slaymaker wrote​:

sub foo {
map {
while (1) {} ;
} @​wits_end ;
}

BEGIN {
die ;
}

Never dies. It sucks up all CPU instead.

This bug is still present, as of the current development version of perl (@​18374).

(gdb) bt
#0 0x00015c64 in Perl_ck_grep ()
#1 0x0000d418 in Perl_convert ()
#2 0x000c79ac in Perl_yyparse ()
#3 0x0001b818 in S_parse_body ()
#4 0x0001a77c in perl_parse ()

[p5pRT]

From @schwern

Bug still present in 5.8.1 RC 2

[p5pRT]

From @rspier

not fixed in 5.8.4
will be fixed in 5.9.2 (DEVEL22511)

[p5pRT]

@rspier - Status changed from 'open' to 'resolved'