From @tonycoz

Created by @tonycoz

fedf30e (v5.21.6-336-gfedf30e)
introduced a memory leak when running the following code​:

PERL_DESTRUCT_LEVEL=2 valgrind -q --leak-check=full ./perl -Ilib -Mwarnings -e0

In blead the reported leaks are​:

==23030== 3,584 (512 direct, 3,072 indirect) bytes in 1 blocks are definitely lost in loss record 12 of 26
==23030== at 0x4C267BB​: calloc (vg_replace_malloc.c​:593)
==23030== by 0x4203A6​: Perl_Slab_Alloc (op.c​:181)
==23030== by 0x428C07​: Perl_newSVOP (op.c​:5807)
==23030== by 0x46F985​: S_force_word (toke.c​:2034)
==23030== by 0x485493​: Perl_yylex (toke.c​:7739)
==23030== by 0x48D5DD​: Perl_yyparse (perly.c​:322)
==23030== by 0x58B9A7​: S_doeval (pp_ctl.c​:3484)
==23030== by 0x5929B9​: Perl_pp_require (pp_ctl.c​:4169)
==23030== by 0x4D630A​: Perl_runops_debug (dump.c​:2231)
==23030== by 0x44788E​: Perl_call_sv (perl.c​:2736)
==23030== by 0x4482A1​: Perl_call_list (perl.c​:4842)
==23030== by 0x42228A​: S_process_special_blocks (op.c​:8899)
==23030==
==23030== 23,552 (1,024 direct, 22,528 indirect) bytes in 2 blocks are definitely lost in loss record 24 of 26
==23030== at 0x4C267BB​: calloc (vg_replace_malloc.c​:593)
==23030== by 0x4203A6​: Perl_Slab_Alloc (op.c​:181)
==23030== by 0x42A193​: Perl_newOP (op.c​:4748)
==23030== by 0x48E642​: Perl_yyparse (perly.y​:996)
==23030== by 0x58B9A7​: S_doeval (pp_ctl.c​:3484)
==23030== by 0x5929B9​: Perl_pp_require (pp_ctl.c​:4169)
==23030== by 0x4D630A​: Perl_runops_debug (dump.c​:2231)
==23030== by 0x44788E​: Perl_call_sv (perl.c​:2736)
==23030== by 0x4482A1​: Perl_call_list (perl.c​:4842)
==23030== by 0x42228A​: S_process_special_blocks (op.c​:8899)
==23030== by 0x43BE95​: Perl_newATTRSUB_x (op.c​:8829)
==23030== by 0x43EA7E​: Perl_utilize (op.c​:6052)
==23030==
==23030== 48,640 (512 direct, 48,128 indirect) bytes in 1 blocks are definitely lost in loss record 25 of 26
==23030== at 0x4C267BB​: calloc (vg_replace_malloc.c​:593)
==23030== by 0x4203A6​: Perl_Slab_Alloc (op.c​:181)
==23030== by 0x428C07​: Perl_newSVOP (op.c​:5807)
==23030== by 0x46F985​: S_force_word (toke.c​:2034)
==23030== by 0x485EFD​: Perl_yylex (toke.c​:7638)
==23030== by 0x48D5DD​: Perl_yyparse (perly.c​:322)
==23030== by 0x58B9A7​: S_doeval (pp_ctl.c​:3484)
==23030== by 0x5929B9​: Perl_pp_require (pp_ctl.c​:4169)
==23030== by 0x4D630A​: Perl_runops_debug (dump.c​:2231)
==23030== by 0x44788E​: Perl_call_sv (perl.c​:2736)
==23030== by 0x4482A1​: Perl_call_list (perl.c​:4842)
==23030== by 0x42228A​: S_process_special_blocks (op.c​:8899)
==23030==
==23030== 64,000 (1,536 direct, 62,464 indirect) bytes in 3 blocks are definitely lost in loss record 26 of 26
==23030== at 0x4C267BB​: calloc (vg_replace_malloc.c​:593)
==23030== by 0x4203A6​: Perl_Slab_Alloc (op.c​:181)
==23030== by 0x42A193​: Perl_newOP (op.c​:4748)
==23030== by 0x4722F9​: Perl_yylex (toke.c​:8243)
==23030== by 0x48D5DD​: Perl_yyparse (perly.c​:322)
==23030== by 0x58B9A7​: S_doeval (pp_ctl.c​:3484)
==23030== by 0x5929B9​: Perl_pp_require (pp_ctl.c​:4169)
==23030== by 0x4D630A​: Perl_runops_debug (dump.c​:2231)
==23030== by 0x44788E​: Perl_call_sv (perl.c​:2736)
==23030== by 0x4482A1​: Perl_call_list (perl.c​:4842)
==23030== by 0x42228A​: S_process_special_blocks (op.c​:8899)
==23030== by 0x43BE95​: Perl_newATTRSUB_x (op.c​:8829)
==23030==

Simple code such as​:

$ valgrind -q --leak-check=full ./perl -e '$x->[1][2]'
==23620== 1,536 (512 direct, 1,024 indirect) bytes in 1 blocks are definitely lost in loss record 3 of 3
==23620== at 0x4C267BB​: calloc (vg_replace_malloc.c​:593)
==23620== by 0x4203A6​: Perl_Slab_Alloc (op.c​:181)
==23620== by 0x428C07​: Perl_newSVOP (op.c​:5807)
==23620== by 0x473AB6​: Perl_yylex (toke.c​:8308)
==23620== by 0x48D5DD​: Perl_yyparse (perly.c​:322)
==23620== by 0x44DEF5​: S_parse_body (perl.c​:2277)
==23620== by 0x44F3AB​: perl_parse (perl.c​:1611)
==23620== by 0x41B971​: main (perlmain.c​:114)
==23620==

demonstrates one point of leakage, I haven't tried to duplicate the
others.

Flags:
    category=core
    severity=medium

Site configuration information for perl 5.21.10:

Configured by tony at Wed Feb 25 15:00:37 AEDT 2015.

Summary of my perl5 (revision 5 version 21 subversion 10) configuration:
  Commit id: 33593911f214382b592d05aa902655301915e666
  Platform:
    osname=linux, osvers=2.6.32-358.el6.x86_64, archname=x86_64-linux-thread-multi
    uname='linux dromedary-001.ams6.corp.booking.com 2.6.32-358.el6.x86_64 #1 smp fri feb 22 00:31:26 utc 2013 x86_64 x86_64 x86_64 gnulinux '
    config_args='-Dprefix= -Uversiononly -Dusedevel -des -Dusethreads -DDEBUGGING=both'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2',
    optimize='-O2 -g',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.4.7 20120313 (Red Hat 4.4.7-11)', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678, doublekind=3
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16, longdblkind=3
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib /lib/../lib64 /usr/lib/../lib64 /lib /lib64 /usr/lib64 /usr/local/lib64
    libs=-lpthread -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.12.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.12'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector'


Characteristics of this binary (from libperl): 
  Compile-time options: DEBUGGING HAS_TIMES MULTIPLICITY PERLIO_LAYERS
                        PERL_DONT_CREATE_GVSV
                        PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
                        PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP
                        PERL_NEW_COPY_ON_WRITE PERL_PRESERVE_IVUV
                        PERL_TRACK_MEMPOOL PERL_USE_DEVEL USE_64_BIT_ALL
                        USE_64_BIT_INT USE_ITHREADS USE_LARGE_FILES
                        USE_LOCALE USE_LOCALE_COLLATE USE_LOCALE_CTYPE
                        USE_LOCALE_NUMERIC USE_LOCALE_TIME USE_PERLIO
                        USE_PERL_ATOF USE_REENTRANT_API
  Built under linux
  Compiled at Feb 25 2015 05:29:40
  @INC:
    lib
    /usr/local/lib/perl5/site_perl/5.21.10/x86_64-linux-thread-multi
    /usr/local/lib/perl5/site_perl/5.21.10
    /usr/local/lib/perl5/5.21.10/x86_64-linux-thread-multi
    /usr/local/lib/perl5/5.21.10
    /usr/local/lib/perl5/site_perl/5.12.3
    /usr/local/lib/perl5/site_perl/5.8.8
    /usr/local/lib/perl5/site_perl
    .

From @iabyn

On Tue, Feb 24, 2015 at 08​:40​:33PM -0800, Tony Cook wrote​:

fedf30e (v5.21.6-336-gfedf30e)
introduced a memory leak when running the following code​:

PERL_DESTRUCT_LEVEL=2 valgrind -q --leak-check=full ./perl -Ilib -Mwarnings -e0

Thanks for spotting.
Fixed with b7613b8.

--
The warp engines start playing up a bit, but seem to sort themselves out
after a while without any intervention from boy genius Wesley Crusher.
  -- Things That Never Happen in "Star Trek" #17

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

@iabyn - Status changed from 'open' to 'pending release'

From @khwilliamson

Thank you for submitting this ticket.

The issue should now be resolved with the release today of Perl v5.22, which is available at http​://www.perl.org/get.html
--
Karl Williamson for the Perl 5 team

@khwilliamson - Status changed from 'pending release' to 'resolved'