utf8::length() bad

[p5pRT]

Migrated from rt.perl.org#3598 (status was 'resolved')

Searchable as RT3598$

[p5pRT]

From [email protected]

Created by [email protected]

Hi,

  % perl -mutf8 -e "print utf8​::length('a')"

causes my cpu to peg, and memory to grow until I break out of it.

I tried running it in gdb, got a segfault report immediately, but the
thing kept running (and sucking memory) until I broke out of it​:

  (gdb) run -mutf8 -e "print utf8​::length('a')"
  Starting program​: /usr/src/perl-5.6.0/perl -mutf8 -e "print utf8​::length('a')"
  Segmentation fault (core dumped)

--- several seconds pass, then I interrupt it ---

  Program received signal SIGINT, Interrupt.
  0x8091349 in Perl_hv_fetch (hv=0x80f08e0, key=0xbffff0e4 "utf8​::", klen=6,
  lval=1) at hv.c​:181
  181 PERL_HASH(hash, key, klen);
  (gdb) where
  #0 0x8091349 in Perl_hv_fetch (hv=0x80f08e0, key=0xbffff0e4 "utf8​::", klen=6,
  lval=1) at hv.c​:181
  #1 0x805fe73 in Perl_gv_fetchpv (nambeg=0x80fcb10 "utf8​::length", add=1,
  sv_type=12) at gv.c​:550
  #2 0x80a11e3 in Perl_sv_2cv (sv=0x80fb010, st=0xbffff224, gvp=0xbffff228,
  lref=1) at sv.c​:4981
  #3 0x80a3fde in Perl_pp_rv2cv () at pp.c​:379
  #4 0x80949ed in Perl_runops_standard () at run.c​:27
  #5 0x805bd4e in S_run_body (oldscope=1) at perl.c​:1401
  #6 0x805bad8 in perl_run (my_perl=0x80f0858) at perl.c​:1325
  #7 0x8059903 in main (argc=4, argv=0xbffff354, env=0xbffff368)
  at perlmain.c​:52

Even though I have my coredumplimit set to zero, when running this from
within gdb, it does dump a small (360k) core file. On a whim, I ran

  jfriedl@​fummy> gdb /usr/src/perl-5.6.0/perl core
  GNU gdb 4.18
  Copyright 1998 Free Software Foundation, Inc.
  This GDB was configured as "i386-mandrake-linux"...

  warning​: core file may not match specified executable file.
  Core was generated by `perl -w test -d /etc/profile.d'.
  Program terminated with signal 11, Segmentation fault.
  Reading symbols from /lib/libnsl.so.1...done.
  Reading symbols from /lib/libdb.so.3...done.
  Reading symbols from /usr/lib/libgdbm.so.2...done.
  Reading symbols from /lib/libdl.so.2...done.
  Reading symbols from /lib/libm.so.6...done.
  Reading symbols from /lib/libc.so.6...done.
  Reading symbols from /lib/libcrypt.so.1...done.
  Reading symbols from /lib/ld-linux.so.2...done.
  #0 0x400fd1f4 in memmove () from /lib/libc.so.6
  (gdb) where
  #0 0x400fd1f4 in memmove () from /lib/libc.so.6
  #1 0x80faf7c in ?? ()
  Cannot access memory at address 0x1.

Which seems odd, to say the least.

  Jeffrey

Perl Info

Flags:
    category=core
    severity=medium

Site configuration information for perl v5.6.0:

Configured by jfriedl at Sat Jul 29 20:09:33 PDT 2000.

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.2.15, archname=i686-linux
    uname='linux fummy.dsl.yahoo.com 2.2.16 #6 smp sun jul 23 11:26:16 pdt 2000 i686 unknown '
    config_args='-ds -e -A optimize=-g'
    hint=previous, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define 
    use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef
  Compiler:
    cc='cc', optimize='-O2 -g', gccversion=pgcc-2.91.66 19990314 (egcs-1.1.2 release)
    cppflags='-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    ccflags ='-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    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=/lib/libc-2.1.1.so, 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 v5.6.0:
    /home/jfriedl/lib/perl
    /home/jfriedl/lib/perl/yahoo
    /usr/local/lib/perl5/5.6.0/i686-linux
    /usr/local/lib/perl5/5.6.0
    /usr/local/lib/perl5/site_perl/5.6.0/i686-linux
    /usr/local/lib/perl5/site_perl/5.6.0
    /usr/local/lib/perl5/site_perl
    .


Environment for perl v5.6.0:
    HOME=/home/jfriedl
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH=/usr/local/pgsql/lib:/home/jfriedl/src/rvplayer5.0
    LOGDIR (unset)
    PATH=/home/jfriedl/bin:/home/jfriedl/common/bin:/usr/local/gcc-2.95.2/bin:.:/usr/local/pgsql/bin:/usr/local/bin:/usr/X11R6/bin:/bin:/usr/bin:/usr/sbin:/sbin:/home/jfriedl/src/rvplayer5.0
    PERLLIB=/home/jfriedl/lib/perl:/home/jfriedl/lib/perl/yahoo
    PERL_BADLANG (unset)
    SHELL=/bin/tcsh

[p5pRT]

From [Unknown Contact. See original ticket]

Jeffrey Friedl (lists.p5p)​:

% perl -mutf8 -e "print utf8​::length('a')"

causes my cpu to peg, and memory to grow until I break out of it.

Oh, *swear*. I know why this is happening, and I'll have a look at it
today if possible.

[p5pRT]

From [Unknown Contact. See original ticket]

Simon Cozens (lists.p5p)​:

Jeffrey Friedl (lists.p5p)​:

% perl -mutf8 -e "print utf8​::length('a')"

causes my cpu to peg, and memory to grow until I break out of it.

Oh, *swear*. I know why this is happening, and I'll have a look at it
today if possible.

Hm, this was more fundamental than I thought. Why do you think you
should be able to call utf8​::length? utf8 is a pragma, not a module
which replaces Perl's builtins.

Nevertheless, recursive AUTOLOADs are certainly bad.

Inline Patch

--- lib/utf8.pm~        Tue Aug  1 15:46:44 2000
+++ lib/utf8.pm Tue Aug  1 15:53:16 2000
@@ -13,7 +13,8 @@

 sub AUTOLOAD {
     require "utf8_heavy.pl";
-    goto &$AUTOLOAD;
+    goto &$AUTOLOAD if defined &$AUTOLOAD;
+    Carp::croak("Undefined subroutine $AUTOLOAD called");
 }

 1;

[p5pRT]

From @jhi

Nevertheless, recursive AUTOLOADs are certainly bad.

--- lib/utf8.pm~ Tue Aug 1 15​:46​:44 2000
+++ lib/utf8.pm Tue Aug 1 15​:53​:16 2000
@​@​ -13,7 +13,8 @​@​

sub AUTOLOAD {
require "utf8_heavy.pl";
- goto &$AUTOLOAD;
+ goto &$AUTOLOAD if defined &$AUTOLOAD;
+ Carp​::croak("Undefined subroutine $AUTOLOAD called");
}

1;

Applied, thanks.