fphttpapp suspect mem leak
lazarus / 38-Networking and Web Programming

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Чебурашка · 2022-02-10 09:30

Hello,

I worked all nite to complete this great program, then I compiled it
with "Use Heaptrc unit (check for mem-leaks) (-gh)" in Lazarus.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  program
project3; uses   fphttpapp; begin end. 
I get this:

Code: Bash  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
 tt@debian:~/Documents/dev$ ./project3Heap dump by heaptrc unit75
memory blocks allocated : 72406/7259273 memory blocks freed     :
72350/725362 unfreed memory blocks : 56True heap size : 163840True
free heap : 163456Should be : 163528Call trace for block
$00007FCED20ECFC0 size 32Call trace for block $00007FCED20ECA80 size
24tt@debian:~/Documents/dev$ 
Is the leak real?

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howardpc · 2022-02-10 10:59

Of course the leak is real.
heaptrc may not catch quite as many potential leaks as valgrind, but
you can't argue with its simple arithmetic: your program allocated 75
memory blocks and did not free them all.
For the reason why, I suppose you have to look at the initialization
and finalization code of fphttpapp and see how your system handles
that code.

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Чебурашка · 2022-02-10 11:09

Quote from: howardpc on February 10, 2022, 11:59:22 amOf course the
leak is real.
heaptrc may not catch quite as many potential leaks as valgrind, but
you can't argue with its simple arithmetic: your program allocated 75
memory blocks and did not free them all.
For the reason why, I suppose you have to look at the initialization
and finalization code of fphttpapp and see how your system handles
that code.

Just to clarify, I did not create fphttpapp on my own, it is a library
unit in fpc package fcl-web.

packages/fcl-web/src/base/fphttpapp.pp

My system is a "Linux debian 4.19.0-18-amd64 #1 SMP Debian 4.19.208-1
(2021-09-29) x86_64 GNU/Linux"

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wp · 2022-02-10 11:11

What is your Lazarus/FPC version, and your OS? I checked Laz-main/FPC-
main, Laz 2.2/FPC 3.2.2, Laz 1.8.4/FPC3.0.4, and in none of them that
memory leak is reported. I am on Windows, though.

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Чебурашка · 2022-02-10 11:20

Quote from: wp on February 10, 2022, 12:11:10 pmWhat is your
Lazarus/FPC version, and your OS? I checked Laz-main/FPC-main, Laz
2.2/FPC 3.2.2, Laz 1.8.4/FPC3.0.4, and in none of them that memory
leak is reported. I am on Windows, though.

tt@debian:~/Documents/dev$ fpc -i
Free Pascal Compiler version 3.0.4

Compiler date      : 2019/01/24
Compiler CPU target: x86_64

Supported targets (targets marked with '{*}' are under development):
  Linux: Linux for x86-64
  FreeBSD: FreeBSD for x86-64
  Win64: Win64 for x64
  Darwin: Darwin for x86_64
  solaris: Solaris for x86-64 {*}
  OpenBSD: OpenBSD for x86-64 {*}
  NetBSD: NetBSD for x86-64 {*}
  DragonFly: DragonFly for x86-64
  iPhoneSim: Darwin/iPhoneSim for x86_64

Supported CPU instruction sets:
  ATHLON64,COREI,COREAVX,COREAVX2

Supported FPU instruction sets:
  SSE64,SSE3,SSSE3,SSE41,SSE42,AVX,AVX2

Supported inline assembler modes:
  STANDARD
  GAS
  INTEL
  ATT

Recognized compiler and RTL features:
  HEAP,INITFINAL,RTTI,CLASSES,EXCEPTIONS,EXITCODE,ANSISTRINGS,WIDESTRI
NGS
  TEXTIO,CONSOLEIO,FILEIO,RANDOM,VARIANTS,OBJECTS,DYNARRAYS,THREADING
 
COMMANDARGS,PROCESSES,STACKCHECK,DYNLIBS,SOFTFPU,OBJECTIVEC1,RESOURCES
  UNICODESTRINGS

Supported ABI targets:
  DEFAULT

Supported Optimizations:
  REGVAR
  STACKFRAME
  PEEPHOLE
  LOOPUNROLL
  TAILREC
  CSE
  DFA
  USERBP
  ORDERFIELDS
  FASTMATH
  REMOVEEMPTYPROCS
  CONSTPROP

Supported Whole Program Optimizations:
  All
  DEVIRTCALLS
  OPTVMTS
  SYMBOLLIVENESS

Supported Microcontroller types:

This program comes under the GNU General Public Licence
For more information read COPYING.v2

Please report bugs in our bug tracker on:
                 http://bugs.freepascal.org

More information may be found on our WWW pages (including directions
for mailing lists useful for asking questions or discussing potential
new features, etc.):
                 http://www.freepascal.org

lazarus is: 2.0.0+dfsg-2 (I think dfsg is debian packaging stuff)
Date: 2019-03-01

tt@debian:~/Documents/dev$ uname -a
Linux debian 4.19.0-18-amd64 #1 SMP Debian 4.19.208-1 (2021-09-29)
x86_64 GNU/Linux

Thank you for the help

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Чебурашка · 2022-02-10 13:31

Sorry guys it seems that this was a know bug in older versions.

https://gitlab.com/freepascal.org/fpc/source/-/issues/33535