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Misleading output for calloc while -Dm in effect #16653

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p5pRT opened this issue Aug 10, 2018 · 8 comments
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@p5pRT p5pRT commented Aug 10, 2018

Migrated from rt.perl.org#133439 (status was 'resolved')

Searchable as RT133439$

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@p5pRT p5pRT commented Aug 10, 2018

From @eserte

This is a bug report for perl from slaven@​rezic.de,
generated with the help of perlbug 1.41 running under perl 5.28.0.


If -Dm is used then calloc() calls are logged like this​:

  0x2cbf90930​: (2217022366) calloc 32808 x 32808 bytes

It looks like approximately 1GB is allocated here. But the actual DEBUG_m
call is the following​:

  DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf "​: (%05ld) calloc %ld x %ld bytes\n",PTR2UV(ptr),(long)PL_an++,(long)count,(long)total_size));

so the last number is not the single element size, but the total size
of the memory allocation.

Probably the output should look different here, for example

  calloc %ld elements totalling %ld bytes

or

  calloc %ld x %ld = %ld bytes", ... count, size, total_size

or so.



Flags​:
  category=core
  severity=low


Site configuration information for perl 5.28.0​:

Configured by eserte at Sat Jun 23 08​:28​:02 CEST 2018.

Summary of my perl5 (revision 5 version 28 subversion 0) configuration​:
 
  Platform​:
  osname=linux
  osvers=3.16.0-4-amd64
  archname=x86_64-linux
  uname='linux cabulja 3.16.0-4-amd64 #1 smp debian 3.16.51-3 (2017-12-13) x86_64 gnulinux '
  config_args='-ds -e -Dprefix=/opt/perl-5.28.0 -Dcf_email=srezic@​cpan.org'
  hint=recommended
  useposix=true
  d_sigaction=define
  useithreads=undef
  usemultiplicity=undef
  use64bitint=define
  use64bitall=define
  uselongdouble=undef
  usemymalloc=n
  default_inc_excludes_dot=define
  bincompat5005=undef
  Compiler​:
  cc='cc'
  ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
  optimize='-O2'
  cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
  ccversion=''
  gccversion='4.9.2'
  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-strong -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/4.9/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib
  libs=-lpthread -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
  perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
  libc=libc-2.19.so
  so=so
  useshrplib=false
  libperl=libperl.a
  gnulibc_version='2.19'
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs
  dlext=so
  d_dlsymun=undef
  ccdlflags='-Wl,-E'
  cccdlflags='-fPIC'
  lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong'


@​INC for perl 5.28.0​:
  /opt/perl-5.28.0/lib/site_perl/5.28.0/x86_64-linux
  /opt/perl-5.28.0/lib/site_perl/5.28.0
  /opt/perl-5.28.0/lib/5.28.0/x86_64-linux
  /opt/perl-5.28.0/lib/5.28.0


Environment for perl 5.28.0​:
  HOME=/home/eserte
  LANG=en_US.UTF-8
  LANGUAGE=en_US​:en
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/usr/local/bin​:/usr/bin​:/bin​:/usr/local/sbin​:/usr/sbin​:/sbin​:/home/eserte/bin/linux-gnu​:/home/eserte/bin/sh​:/home/eserte/bin​:/home/eserte/bin/pistachio-perl/bin​:/usr/games​:/home/eserte/devel
  PERLDOC=-MPod​::Perldoc​::ToTextOverstrike
  PERL_BADLANG (unset)
  SHELL=/bin/zsh

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@p5pRT p5pRT commented Sep 6, 2018

From @tonycoz

On Fri, 10 Aug 2018 06​:50​:56 -0700, slaven@​rezic.de wrote​:

If -Dm is used then calloc() calls are logged like this​:

0x2cbf90930​: (2217022366) calloc 32808 x 32808 bytes

It looks like approximately 1GB is allocated here. But the actual
DEBUG_m
call is the following​:

DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf "​: (%05ld) calloc %ld
x %ld
bytes\n",PTR2UV(ptr),(long)PL_an++,(long)count,(long)total_size));

so the last number is not the single element size, but the total size
of the memory allocation.

Probably the output should look different here, for example

calloc %ld elements totalling %ld bytes

or

calloc %ld x %ld = %ld bytes", ... count, size, total_size

or so.

Something like the attached?

Tony

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@p5pRT p5pRT commented Sep 6, 2018

From @tonycoz

0001-perl-133439-fix-Dm-reporting-for-calloc.patch
From 75b5f4074fce363842f2171e79c1b39b330b6ea4 Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Thu, 6 Sep 2018 14:05:20 +1000
Subject: (perl #133439) fix -Dm reporting for calloc()

a) report both the size and count, and the total allocated rather than
   just the count and total allocated, which was displayed in a
   misleading fashion

b) use %zu formatting to match the original types (size_t) and remove
   the casts to long, which can lose information on Win32, where
   long is 32-bits on x64 builds.
---
 util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/util.c b/util.c
index ff88a54bf6..a9bf9b8609 100644
--- a/util.c
+++ b/util.c
@@ -439,7 +439,7 @@ Perl_safesyscalloc(MEM_SIZE count, MEM_SIZE size)
 	ptr = (Malloc_t)PerlMem_calloc(count ? count : 1, size ? size : 1);
 #endif
     PERL_ALLOC_CHECK(ptr);
-    DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) calloc %ld x %ld bytes\n",PTR2UV(ptr),(long)PL_an++,(long)count,(long)total_size));
+    DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) calloc %zu x %zu = %zu bytes\n",PTR2UV(ptr),(long)PL_an++, count, size, total_size));
     if (ptr != NULL) {
 #ifdef USE_MDH
 	{
-- 
2.11.0

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@p5pRT p5pRT commented Sep 6, 2018

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

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@p5pRT p5pRT commented Oct 5, 2018

From @tonycoz

On Wed, 05 Sep 2018 21​:06​:12 -0700, tonyc wrote​:

On Fri, 10 Aug 2018 06​:50​:56 -0700, slaven@​rezic.de wrote​:

If -Dm is used then calloc() calls are logged like this​:

0x2cbf90930​: (2217022366) calloc 32808 x 32808 bytes

It looks like approximately 1GB is allocated here. But the actual
DEBUG_m
call is the following​:

DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf "​: (%05ld) calloc %ld
x %ld
bytes\n",PTR2UV(ptr),(long)PL_an++,(long)count,(long)total_size));

so the last number is not the single element size, but the total size
of the memory allocation.

Probably the output should look different here, for example

calloc %ld elements totalling %ld bytes

or

calloc %ld x %ld = %ld bytes", ... count, size, total_size

or so.

Something like the attached?

Applied as 2273039.

Tony

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@p5pRT p5pRT commented Oct 5, 2018

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

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@p5pRT p5pRT commented May 22, 2019

From @khwilliamson

Thank you for filing this report. You have helped make Perl better.

With the release today of Perl 5.30.0, this and 160 other issues have been
resolved.

Perl 5.30.0 may be downloaded via​:
https://metacpan.org/release/XSAWYERX/perl-5.30.0

If you find that the problem persists, feel free to reopen this ticket.

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@p5pRT p5pRT commented May 22, 2019

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

@p5pRT p5pRT closed this May 22, 2019
@p5pRT p5pRT added the Severity Low label Oct 19, 2019
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