op/threads.t segfaults with threads and mymalloc

[p5pRT]

Migrated from rt.perl.org#75972 (status was 'open')

Searchable as RT75972$

[p5pRT]

From perl@profvince.com

Created by perl@profvince.com

The following code, which is a reduced testcase for the op/threads.t failure, segfaults for a perl built with threads and mymalloc enabled :

  #!perl
 
  # Requires threads and mymalloc
 
  use strict;
  use warnings;
  use threads;
 
  my @​t;
  push @​t, threads->create( sub { require IO }) for 1 .. 1000;
  $_->join for grep defined, @​t;

It also sometimes aborts with this assertion failure :

  assertion botched (free()ed/realloc()ed-away memory was overwritten?)​: !(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) || !cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) + ((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof (unsigned int))) + sizeof (unsigned int), fill_deadbeef) (malloc.c​:1546)

Valgrind says :

...
==22779== Invalid read of size 4
==22779== at 0x5533F8​: Perl_hv_common (hv.c​:361)
==22779== by 0x464F55​: perl_get_emergency_buffer (malloc.c​:1160)
==22779== by 0x4656B9​: emergency_sbrk (malloc.c​:1256)
==22779== by 0x46688B​: getpages (malloc.c​:1717)
==22779== by 0x46747F​: morecore (malloc.c​:1965)
==22779== by 0x465C60​: Perl_malloc (malloc.c​:1477)
==22779== by 0x5D6008​: Perl_ptr_table_store (sv.c​:10840)
==22779== by 0x55300D​: Perl_he_dup (hv.c​:175)
==22779== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==22779== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==22779== by 0x5D59D2​: Perl_gp_dup (sv.c​:10694)
==22779== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==22779== Address 0xabababababababb7 is not stack'd, malloc'd or (recently) free'd
==22779==
==22779==
==22779== Process terminating with default action of signal 11 (SIGSEGV)
==22779== General Protection Fault
==22779== at 0x5533F8​: Perl_hv_common (hv.c​:361)
==22779== by 0x464F55​: perl_get_emergency_buffer (malloc.c​:1160)
==22779== by 0x4656B9​: emergency_sbrk (malloc.c​:1256)
==22779== by 0x46688B​: getpages (malloc.c​:1717)
==22779== by 0x46747F​: morecore (malloc.c​:1965)
==22779== by 0x465C60​: Perl_malloc (malloc.c​:1477)
==22779== by 0x5D6008​: Perl_ptr_table_store (sv.c​:10840)
==22779== by 0x55300D​: Perl_he_dup (hv.c​:175)
==22779== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==22779== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==22779== by 0x5D59D2​: Perl_gp_dup (sv.c​:10694)
==22779== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==22779==
==22779== HEAP SUMMARY​:
...

Perl Info

Flags:
    category=core
    severity=low

Site configuration information for perl 5.13.2:

Configured by vince at Tue Jun 22 23:29:08 CEST 2010.

Summary of my perl5 (revision 5 version 13 subversion 2) configuration:
  Commit id: e4b5ce810b542fc115cb7db392c771730fc4f98e
  Platform:
    osname=linux, osvers=2.6.34-fuuka.profvince.com, archname=x86_64-linux-thread-multi
    uname='linux fuuka 2.6.34-fuuka.profvince.com #1 smp wed jun 16 22:13:24 cest 2010 x86_64 intel(r) core(tm)2 duo cpu e6750 @ 2.66ghz genuineintel gnulinux '
    config_args='-Doptimize= -g3 -des -Dusedevel -Dman1dir=none -Dman3dir=none -Dcf_email=vpit@cpan.org -Dmydomain=fuuka.profvince.com -Dusedevel -DDEBUGGING -Dusethreads -Dusemmorebits -Dusemymalloc -Dprefix=/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=y, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize=' -g3',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector'
    ccversion='', gccversion='4.4.4', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    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 /lib /usr/lib /lib64 /usr/lib64 /usr/local/lib64
    libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc -lgdbm_compat
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=/lib/libc-2.11.2.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.11.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared  -g3 -L/usr/local/lib -fstack-protector'

Locally applied patches:
    


@INC for perl 5.13.2:
    lib
    /home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8/lib/site_perl/5.13.2/x86_64-linux-thread-multi
    /home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8/lib/site_perl/5.13.2
    /home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8/lib/5.13.2/x86_64-linux-thread-multi
    /home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8/lib/5.13.2
    .


Environment for perl 5.13.2:
    HOME=/home/vince
    LANG=fr_FR.UTF-8
    LANGUAGE (unset)
    LC_ALL=fr_FR.UTF-8
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/vince/bin:/home/vince/perl/builds/bin:/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.4.4:/opt/intel/cce/10.1.018/bin:/usr/games/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

[p5pRT]

From perl@profvince.com

Valgrind with more callers :

...
==23560== Invalid read of size 4
==23560== at 0x5533F8​: Perl_hv_common (hv.c​:361)
==23560== by 0x464F55​: perl_get_emergency_buffer (malloc.c​:1160)
==23560== by 0x4656B9​: emergency_sbrk (malloc.c​:1256)
==23560== by 0x46688B​: getpages (malloc.c​:1717)
==23560== by 0x46747F​: morecore (malloc.c​:1965)
==23560== by 0x465C60​: Perl_malloc (malloc.c​:1477)
==23560== by 0x584CC9​: S_more_sv (sv.c​:266)
==23560== by 0x5D70B6​: S_sv_dup_common (sv.c​:11039)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D59D2​: Perl_gp_dup (sv.c​:10694)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D83A1​: S_sv_dup_common (sv.c​:11181)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x4D8DD7​: Perl_padlist_dup (pad.c​:1878)
==23560== by 0x5D9876​: S_sv_dup_common (sv.c​:11329)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x55302B​: Perl_he_dup (hv.c​:177)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D9603​: S_sv_dup_common (sv.c​:11316)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D9603​: S_sv_dup_common (sv.c​:11316)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D83A1​: S_sv_dup_common (sv.c​:11181)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5DD13D​: perl_clone (sv.c​:12157)
==23560== by 0x6466F55​: S_ithread_create (threads.xs​:769)
==23560== Address 0xabababababababb7 is not stack'd, malloc'd or
(recently) free'd
==23560==
==23560==
==23560== Process terminating with default action of signal 11 (SIGSEGV)
==23560== General Protection Fault
==23560== at 0x5533F8​: Perl_hv_common (hv.c​:361)
==23560== by 0x464F55​: perl_get_emergency_buffer (malloc.c​:1160)
==23560== by 0x4656B9​: emergency_sbrk (malloc.c​:1256)
==23560== by 0x46688B​: getpages (malloc.c​:1717)
==23560== by 0x46747F​: morecore (malloc.c​:1965)
==23560== by 0x465C60​: Perl_malloc (malloc.c​:1477)
==23560== by 0x584CC9​: S_more_sv (sv.c​:266)
==23560== by 0x5D70B6​: S_sv_dup_common (sv.c​:11039)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D59D2​: Perl_gp_dup (sv.c​:10694)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D83A1​: S_sv_dup_common (sv.c​:11181)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x4D8DD7​: Perl_padlist_dup (pad.c​:1878)
==23560== by 0x5D9876​: S_sv_dup_common (sv.c​:11329)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x55302B​: Perl_he_dup (hv.c​:177)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D9603​: S_sv_dup_common (sv.c​:11316)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D9603​: S_sv_dup_common (sv.c​:11316)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5D5A34​: Perl_gp_dup (sv.c​:10696)
==23560== by 0x5D8969​: S_sv_dup_common (sv.c​:11194)
==23560== by 0x5D9A7C​: Perl_sv_dup_inc (sv.c​:11351)
==23560== by 0x5531E2​: Perl_he_dup (hv.c​:205)
==23560== by 0x5D92D6​: S_sv_dup_common (sv.c​:11273)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5D83A1​: S_sv_dup_common (sv.c​:11181)
==23560== by 0x5D9ADF​: Perl_sv_dup (sv.c​:11357)
==23560== by 0x5DD13D​: perl_clone (sv.c​:12157)
==23560== by 0x6466F55​: S_ithread_create (threads.xs​:769)
==23560==
==23560== HEAP SUMMARY​:
...

[p5pRT]

From @jkeenan

On Tue Jun 22 14​:58​:31 2010, perl@​profvince.com wrote​:

This is a bug report for perl from perl@​profvince.com,
generated with the help of perlbug 1.39 running under perl 5.13.2.

-----------------------------------------------------------------
[Please describe your issue here]

The following code, which is a reduced testcase for the op/threads.t
failure, segfaults for a perl built with threads and mymalloc enabled
:

#!perl

# Requires threads and mymalloc

use strict;
use warnings;
use threads;

my @​t;
push @​t, threads->create( sub { require IO }) for 1 .. 1000;
$_->join for grep defined, @​t;

It also sometimes aborts with this assertion failure :

assertion botched (free()ed/realloc()ed-away memory was overwritten?)​:
!(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) ||
!cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) +
((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof
(unsigned int))) + sizeof (unsigned int), fill_deadbeef)
(malloc.c​:1546)

Valgrind says :

[snip Valgrind output; see OP]

-----------------------------------------------------------------
---
Flags​:
category=core
severity=low
---
Site configuration information for perl 5.13.2​:

Configured by vince at Tue Jun 22 23​:29​:08 CEST 2010.

Summary of my perl5 (revision 5 version 13 subversion 2)
configuration​:
Commit id​: e4b5ce8
Platform​:
osname=linux, osvers=2.6.34-fuuka.profvince.com, archname=x86_64-
linux-thread-multi
uname='linux fuuka 2.6.34-fuuka.profvince.com #1 smp wed jun 16
22​:13​:24 cest 2010 x86_64 intel(r) core(tm)2 duo cpu e6750 @​ 2.66ghz
genuineintel gnulinux '
config_args='-Doptimize= -g3 -des -Dusedevel -Dman1dir=none
-Dman3dir=none -Dcf_email=vpit@​cpan.org -Dmydomain=fuuka.profvince.com
-Dusedevel -DDEBUGGING -Dusethreads -Dusemmorebits -Dusemymalloc
-Dprefix=/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-ge4b5ce8'
hint=recommended, useposix=true, d_sigaction=define
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define,
usesocks=undef
use64bitint=define, use64bitall=define, uselongdouble=undef
usemymalloc=y, bincompat5005=undef
Compiler​:
cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-
strict-aliasing -pipe -fstack-protector -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
optimize=' -g3',
cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-
aliasing -pipe -fstack-protector'
ccversion='', gccversion='4.4.4', gccosandvers=''
intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
d_longlong=define, longlongsize=8, d_longdbl=define,
longdblsize=16
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 /lib /usr/lib /lib64 /usr/lib64
/usr/local/lib64
libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
-lgdbm_compat
perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
libc=/lib/libc-2.11.2.so, so=so, useshrplib=false,
libperl=libperl.a
gnulibc_version='2.11.2'
Dynamic Linking​:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
cccdlflags='-fPIC', lddlflags='-shared -g3 -L/usr/local/lib
-fstack-protector'

Locally applied patches​:

---
@​INC for perl 5.13.2​:
lib
/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-
ge4b5ce8/lib/site_perl/5.13.2/x86_64-linux-thread-multi
/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-
ge4b5ce8/lib/site_perl/5.13.2
/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-
ge4b5ce8/lib/5.13.2/x86_64-linux-thread-multi
/home/vince/perl/builds/dbg/thr/64/mm/5.13.1-223-
ge4b5ce8/lib/5.13.2
.

---
Environment for perl 5.13.2​:
HOME=/home/vince
LANG=fr_FR.UTF-8
LANGUAGE (unset)
LC_ALL=fr_FR.UTF-8
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/home/vince/bin​:/home/vince/perl/builds/bin​:/usr/local/bin​:/usr/bin​:/bin​:/opt/bin​:/usr/x86_64-
pc-linux-gnu/gcc-bin/4.4.4​:/opt/intel/cce/10.1.018/bin​:/usr/games/bin
PERL_BADLANG (unset)
SHELL=/bin/bash

This problem appears to still be present in blead.

At commit 4b76cb9, I configured as follows​:

#####
sh ./Configure -des -Dusedevel -Doptimize=-g3 -DDEBUGGING -Dusethreads -Dusemmorebits -Dusemymalloc
#####

... which was as close to the OP's configuration as I could understand. I built perl successfully. All tests in t/op/threads.t passed. However, I also tried a script based on the OP's script; see attached.

At 1000 repetitions, the program completed successfully. However at 5000 reps I got a seg fault and at 10000 I got something like the weird results the OP posted.

#####
[perl] 1011 $ ./perl -Ilib ../p5p/75972-threads.pl 5000
Segmentation fault
[perl] 1012 $ ./perl -Ilib ../p5p/75972-threads.pl 10000
assertion botched (assertion botched (free()ed/realloc()ed-away memory was overwrittenfree()ed/realloc()ed-away memory was overwritten?)​: ?)​: !(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) || !cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) + ((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof (unsigned int))) + sizeof (unsigned int), fill_deadbeef)!(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) || !cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) + ((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof (unsigned int))) + sizeof (unsigned int), fill_deadbeef) ( (malloc.cmalloc.c​::13451345)
)
Aborted
#####

Thank you very much.
Jim Keenan

[p5pRT]

From @jkeenan

75972-threads.pl

[p5pRT]

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

[p5pRT]

From @jkeenan

On Wed Dec 11 19​:05​:02 2013, jkeenan wrote​:

This problem appears to still be present in blead.

At commit 4b76cb9, I configured as
follows​:

#####
sh ./Configure -des -Dusedevel -Doptimize=-g3 -DDEBUGGING -Dusethreads
-Dusemmorebits -Dusemymalloc
#####

... which was as close to the OP's configuration as I could
understand. I built perl successfully. All tests in t/op/threads.t
passed. However, I also tried a script based on the OP's script; see
attached.

At 1000 repetitions, the program completed successfully. However at
5000 reps I got a seg fault and at 10000 I got something like the
weird results the OP posted.

#####
[perl] 1011 $ ./perl -Ilib ../p5p/75972-threads.pl 5000
Segmentation fault
[perl] 1012 $ ./perl -Ilib ../p5p/75972-threads.pl 10000
assertion botched (assertion botched (free()ed/realloc()ed-away memory
was overwrittenfree()ed/realloc()ed-away memory was overwritten?)​: ?)​:
!(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) ||
!cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) +
((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof
(unsigned int))) + sizeof (unsigned int),
fill_deadbeef)!(MallocCfg[MallocCfg_filldead] &&
MallocCfg[MallocCfg_fillcheck]) || !cmp_pat_4bytes((unsigned char*)(p
+ 1), (((1 << ((bucket) >> 0)) + ((bucket >= 15 * 1) ? 4096 : 0)) -
(sizeof(union overhead) + sizeof (unsigned int))) + sizeof (unsigned
int), fill_deadbeef) ( (malloc.cmalloc.c​::13451345)
)
Aborted
#####

I next configured the same way except omitting the '-mymalloc'​:

#####
sh ./Configure -des -Dusedevel -Doptimize=-g3 -DDEBUGGING -Dusethreads -Dusemmorebits
#####

This time, my test script completed successfully at each of 1000, 5000, and 10000 reps. (The 10,000 rep case took 2​:48 to run on dromedary.)

So '-Dmymalloc' appears to be the most problematic argument.

Thank you very much.
Jim Keenan

[p5pRT]

From @jkeenan

On Thu, 12 Dec 2013 03​:18​:20 GMT, jkeenan wrote​:

On Wed Dec 11 19​:05​:02 2013, jkeenan wrote​:

This problem appears to still be present in blead.

At commit 4b76cb9, I configured as
follows​:

#####
sh ./Configure -des -Dusedevel -Doptimize=-g3 -DDEBUGGING
-Dusethreads
-Dusemmorebits -Dusemymalloc
#####

... which was as close to the OP's configuration as I could
understand. I built perl successfully. All tests in t/op/threads.t
passed. However, I also tried a script based on the OP's script; see
attached.

At 1000 repetitions, the program completed successfully. However at
5000 reps I got a seg fault and at 10000 I got something like the
weird results the OP posted.

#####
[perl] 1011 $ ./perl -Ilib ../p5p/75972-threads.pl 5000
Segmentation fault
[perl] 1012 $ ./perl -Ilib ../p5p/75972-threads.pl 10000
assertion botched (assertion botched (free()ed/realloc()ed-away
memory
was overwrittenfree()ed/realloc()ed-away memory was overwritten?)​:
?)​:
!(MallocCfg[MallocCfg_filldead] && MallocCfg[MallocCfg_fillcheck]) ||
!cmp_pat_4bytes((unsigned char*)(p + 1), (((1 << ((bucket) >> 0)) +
((bucket >= 15 * 1) ? 4096 : 0)) - (sizeof(union overhead) + sizeof
(unsigned int))) + sizeof (unsigned int),
fill_deadbeef)!(MallocCfg[MallocCfg_filldead] &&
MallocCfg[MallocCfg_fillcheck]) || !cmp_pat_4bytes((unsigned char*)(p
+ 1), (((1 << ((bucket) >> 0)) + ((bucket >= 15 * 1) ? 4096 : 0)) -
(sizeof(union overhead) + sizeof (unsigned int))) + sizeof (unsigned
int), fill_deadbeef) ( (malloc.cmalloc.c​::13451345)
)
Aborted
#####

I next configured the same way except omitting the '-mymalloc'​:

Should have typed​: "except omitting the '-Dusemymalloc'​:"

#####
sh ./Configure -des -Dusedevel -Doptimize=-g3 -DDEBUGGING -Dusethreads
-Dusemmorebits
#####

This time, my test script completed successfully at each of 1000,
5000, and 10000 reps. (The 10,000 rep case took 2​:48 to run on
dromedary.)

So '-Dmymalloc' appears to be the most problematic argument.

Should have typed​: "So '-Dusemymalloc' appears to be the most problematic argument."

Thank you very much.
Jim Keenan

--
James E Keenan (jkeenan@​cpan.org)