Bug #69998 [Opn]: curl multi leaking memory

From: Date: Thu, 09 Jul 2015 15:33:28 +0000
Subject: Bug #69998 [Opn]: curl multi leaking memory
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-194257@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=69998&edit=1

 ID:                 69998
 User updated by:    fred_brownuk at yahoo dot co dot uk
 Reported by:        fred_brownuk at yahoo dot co dot uk
 Summary:            curl multi leaking memory
 Status:             Open
 Type:               Bug
 Package:            cURL related
 Operating System:   Mint 17.1 & Debian 6 LTS
 PHP Version:        7.0.0alpha2
 Block user comment: N
 Private report:     N

 New Comment:

I get the issue with both versions of libcurl I've tried, my distro has 7.35.0 and I've
also tried with the newer 7.43.0

Incidentally, I've just tried building php 7 from git master, the errors regarding
"Conditional jump or move depends on uninitialised value(s)" are no longer present, but
the other issues remain.


Previous Comments:
------------------------------------------------------------------------
[2015-07-09 15:12:02] cmb@php.net

I get a similar valgrind report when running the supplied test
script. It seems to me that the "Conditional jump or move depends
on uninitialised value(s)" might be a bogus warning (aka. false
positive). The leaks (64 bytes in 2 blocks for me), however, occur
also for an empty PHP script.

Fred, which libcurl do you use?

------------------------------------------------------------------------
[2015-07-09 11:33:55] fred_brownuk at yahoo dot co dot uk

Thanks for looking. Sorry this doesn't mean much to me, but here you go.

==15597== Memcheck, a memory error detector
==15597== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==15597== Using Valgrind-3.10.0.SVN and LibVEX; rerun with -h for copyright info
==15597== Command: curlphpalpha2/bin/php bug69998.php
==15597== 
==15597== Conditional jump or move depends on uninitialised value(s)
==15597==    at 0x5ACD79: curl_compare_resources (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x8AC3B4: zend_llist_del_element (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x5AD01F: zif_curl_multi_remove_handle (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x90C5AC: ZEND_DO_ICALL_SPEC_HANDLER (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x8FCFEA: execute_ex (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x95BFC2: zend_execute (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x8BA22D: zend_execute_scripts (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x851B4F: php_execute_script (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x95D822: do_cli (in /home/fred/curlphpalpha2/bin/php)
==15597==    by 0x43C1FA: main (in /home/fred/curlphpalpha2/bin/php)
==15597== 
resource(5) of type (curl)
resource(5) of type (curl)
354976
355320
355344
355368
355392
356056
356080
356104
356128
356152
==15597== 
==15597== HEAP SUMMARY:
==15597==     in use at exit: 1,030 bytes in 22 blocks
==15597==   total heap usage: 32,419 allocs, 32,397 frees, 3,405,857 bytes allocated
==15597== 
==15597== LEAK SUMMARY:
==15597==    definitely lost: 0 bytes in 0 blocks
==15597==    indirectly lost: 0 bytes in 0 blocks
==15597==      possibly lost: 0 bytes in 0 blocks
==15597==    still reachable: 1,030 bytes in 22 blocks
==15597==         suppressed: 0 bytes in 0 blocks
==15597== Reachable blocks (those to which a pointer was found) are not shown.
==15597== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==15597== 
==15597== For counts of detected and suppressed errors, rerun with: -v
==15597== Use --track-origins=yes to see where uninitialised values come from
==15597== ERROR SUMMARY: 11 errors from 1 contexts (suppressed: 0 from 0)

------------------------------------------------------------------------
[2015-07-09 11:08:13] kalle@php.net

Can you confirm this leak with a valgrind output or similar? valgrind --leak-check=yes php
bug69998.php should be sufficient to confirm this

------------------------------------------------------------------------
[2015-07-05 22:56:16] fred_brownuk at yahoo dot co dot uk

Description:
------------
On both 7.0.0alpha1 and 7.0.0alpha2 the curl multi interface is holding onto resources.

A curl handle added to a multi handle with curl_multi_add_handle() should be fully independent once
released from the multi handle with curl_multi_remove_handle(). Curl handles are not being released
properly.

Repeated use of the multi interface is leaking memory.

Test script:
---------------
// curl multi holding onto curl handles
$mh=curl_multi_init();
$ch = curl_init();
curl_multi_add_handle($mh, $ch);
curl_multi_remove_handle($mh, $ch);
var_dump($ch);
curl_close($ch);
var_dump($ch);
curl_multi_close($mh);

// show memory leak
for ($l=0; $l<10; $l++) {
    $mh=curl_multi_init();
    $ch = curl_init();
    curl_multi_add_handle($mh, $ch);
    curl_multi_remove_handle($mh, $ch);
    curl_close($ch);
    curl_multi_close($mh);
    echo memory_get_usage().PHP_EOL;
}

Expected result:
----------------
resource(5) of type (curl)
resource(5) of type (Unknown)
374192
374192
374192
374192
374192
374192
374192
374192
374192
374192

Actual result:
--------------
resource(5) of type (curl)
resource(5) of type (curl)
374192
374536
374560
374584
374608
375272
375296
375320
375344
375368


------------------------------------------------------------------------



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