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Blessed reference to anonymous glob causes seg fault or "Attempt to free unrefer #7144

Closed p5pRT closed 20 years ago

p5pRT commented 20 years ago

Migrated from rt.perl.org#27268 (status was 'resolved')

Searchable as RT27268$

p5pRT commented 20 years ago

From demerphq@hotmail.com

This is a bug report for perl from demerphq@​hotmail.com\, generated with the help of perlbug 1.33 running under perl v5.6.1.

On 5.8.2 (AS 808)​:

D​:\Temp>perl -MSymbol -e "my $x=bless \gensym\,'t'; *$$x=$x" Attempt to free unreferenced scalar​: SV 0x15d4f38 during global destruction.

on 5.6.1 (AS 635)​: D​:\Temp>perl -MSymbol -e "my $x=bless \gensym\,'t'; *$$x=$x" (SEGFAULTS)

This also applies to non Win32 builds. All versions of perl this was checked against threw errors regardless of perl version or OS.

Regards\, Yves

Flags​:   category=core   severity=low

Site configuration information for perl v5.6.1​:

Configured by ActiveState at Mon Jun 17 21​:32​:50 2002.

Summary of my perl5 (revision 5 version 6 subversion 1) configuration​:   Platform​:   osname=MSWin32\, osvers=4.0\, archname=MSWin32-x86-multi-thread   uname=''   config_args='undef'   hint=recommended\, useposix=true\, d_sigaction=undef   usethreads=undef use5005threads=undef useithreads=define usemultiplicity=define   useperlio=undef d_sfio=undef uselargefiles=undef usesocks=undef   use64bitint=undef use64bitall=undef uselongdouble=undef   Compiler​:   cc='cl'\, ccflags ='-nologo -O1 -MD -DNDEBUG -DWIN32 -D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DPERL_MSVCRT_READFIX'\,   optimize='-O1 -MD -DNDEBUG'\,   cppflags='-DWIN32'   ccversion=''\, gccversion=''\, gccosandvers=''   intsize=4\, longsize=4\, ptrsize=4\, doublesize=8\, byteorder=1234   d_longlong=undef\, longlongsize=8\, d_longdbl=define\, longdblsize=10   ivtype='long'\, ivsize=4\, nvtype='double'\, nvsize=8\, Off_t='off_t'\, lseeksize=4   alignbytes=8\, usemymalloc=n\, prototype=define   Linker and Libraries​:   ld='link'\, ldflags ='-nologo -nodefaultlib -release
-libpath​:"E​:\Perl\lib\CORE" -machine​:x86'   libpth="E​:\DotNet\FrameworkSDK\Lib\" "E​:\Perl\lib\CORE"   libs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib uuid.lib wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib   perllibs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib uuid.lib wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib   libc=msvcrt.lib\, so=dll\, useshrplib=yes\, libperl=perl56.lib   Dynamic Linking​:   dlsrc=dl_win32.xs\, dlext=dll\, d_dlsymun=undef\, ccdlflags=' '   cccdlflags=' '\, lddlflags='-dll -nologo -nodefaultlib -release
-libpath​:"E​:\Perl\lib\CORE" -machine​:x86'

Locally applied patches​:   ACTIVEPERL_LOCAL_PATCHES_ENTRY

@​INC for perl v5.6.1​:   D​:\development\perl\devlib   E​:/Perl/lib   E​:/Perl/site/lib   .

Environment for perl v5.6.1​:   HOME (unset)   LANG (unset)   LANGUAGE (unset)   LD_LIBRARY_PATH (unset)   LOGDIR (unset)  
PATH=E​:\Editors\UltraEdit;E​:\DotNet\Common7\IDE;E​:\DotNet\VC7\BIN;E​:\DotNet\Common7\Tools;E​:\DotNet\Common7\Tools\bin\prerelease;E​:\DotNet\Common7\Tools\bin;E​:\DotNet\FrameworkSDK\bin;C​:\WINNT\Microsoft.NET\Framework\v1.0.3705;e​:\sybase\OCS-12_0\dll;e​:\sybase\OCS-12_0\bin;C​:\WINNT\system32;C​:\Program Files\Symantec\pcAnywhere\;C​:\WINNT;C​:\WINNT\System32\Wbem;E​:\Editors\ULTRAE~1;E​:\Perforce;E​:\Perl\bin\;E​:\bin;E​:\cygwin\bin;E​:\perl58\bin;E​:\sybase;E​:\sybase\sqladvantage;e​:\sybase\ASEP;e​:\sybase\SQLRemote\dll;perl\bleadperl\bin   PERL5LIB=D​:\development\perl\devlib   PERL5_CPANPLUS_CONFIG=e​:\.cpanplus\config   PERL_BADLANG (unset)   SHELL (unset)

_________________________________________________________________ MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*. http​://join.msn.com/?page=features/virus

p5pRT commented 20 years ago

From @iabyn

On Mon\, Mar 01\, 2004 at 03​:19​:09PM -0000\, Yves Orton wrote​:

On 5.8.2 (AS 808)​:

D​:\Temp>perl -MSymbol -e "my $x=bless \gensym\,'t'; *$$x=$x" Attempt to free unreferenced scalar​: SV 0x15d4f38 during global destruction.

on 5.6.1 (AS 635)​: D​:\Temp>perl -MSymbol -e "my $x=bless \gensym\,'t'; *$$x=$x" (SEGFAULTS)

The following change fixes the warning; I'm assuming the coredump has already been fixed.

Dave.

Change 22591 by davem@​davem-percy on 2004/03/26 01​:16​:55

  [perl #27268] Blessed reference to anonymous glob   Stop *$$x=$x giving "Attempt to free unreferenced scalar" warning

Affected files ...

... //depot/perl/sv.c#731 edit ... //depot/perl/t/op/ref.t#21 edit

Differences ...

==== //depot/perl/sv.c#731 (text) ====

@​@​ -410\,6 +410\,7 @​@​   (GvCV(sv) && SvOBJECT(GvCV(sv))) )   {   DEBUG_D((PerlIO_printf(Perl_debug_log\, "Cleaning named glob object​:\n ")\, sv_dump(sv))); + SvFLAGS(sv) |= SVf_BREAK;   SvREFCNT_dec(sv);   }   }

==== //depot/perl/t/op/ref.t#21 (xtext) ====

@​@​ -5\,7 +5\,7 @​@​   @​INC = qw(. ../lib); }

-print "1..68\n"; +print "1..69\n";

require 'test.pl';

@​@​ -357\,6 +357\,16 @​@​ if ($? != 0) { print "not " }; print "ok "\,++$test\," - coredump on typeglob = (SvRV && !SvROK)\n";

+# bug #27268​: freeing self-referential typeglobs could trigger +# "Attempt to free unreferenced scalar" warnings + +$result = runperl( + prog => 'use Symbol;my $x=bless \gensym\,"t"; print;*$$x=$x'\, + stderr => 1 +); +print "not " if length $result; +print "ok "\,++$test\," - freeing self-referential typeglob\n"; +print "# got​: $result\n" if length $result;

# test global destruction

p5pRT commented 20 years ago

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

p5pRT commented 20 years ago

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