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Bug #60821 Initialize interned string buffer to avoid valgrind warnings
Submitted: 2012-01-20 18:49 UTC Modified: 2012-01-23 08:28 UTC
From: uw@php.net Assigned: uw (profile)
Status: Closed Package: APC (PECL)
PHP Version: 5.4SVN-2012-01-20 (SVN) OS:
Private report: No CVE-ID: None
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 [2012-01-20 18:49 UTC] uw@php.net 
Description:
------------
APC: pecl/svn - trunk (Revision 322504)
PHP: 5_4, svn - PHP 5.4.0RC7-dev
Static build: ./configure  --enable-apc --enable-debug --enable-maintainer-zts

Valgrind barks at APC, like this:

==31961== Conditional jump or move depends on uninitialised value(s)
==31961==    at 0x81B137A: apc_new_interned_string (apc_string.c:82)
==31961==    by 0x81A02D4: apc_string_pmemcpy (apc_compile.c:283)
==31961==    by 0x81A054B: my_copy_zval (apc_compile.c:338)
==31961==    by 0x819FFC5: my_copy_zval_ptr (apc_compile.c:219)
==31961==    by 0x81A1A51: my_copy_hashtable_ex (apc_compile.c:925)
==31961==    by 0x81A05D4: my_copy_zval (apc_compile.c:349)
==31961==    by 0x81A1C52: apc_copy_zval (apc_compile.c:990)
==31961==    by 0x819E6A1: apc_cache_store_zval (apc_cache.c:1114)
==31961==    by 0x819E8A1: apc_cache_make_user_entry (apc_cache.c:1158)
==31961==    by 0x8197464: _apc_store (php_apc.c:610)
==31961==    by 0x81977AC: apc_store_helper (php_apc.c:669)
==31961==    by 0x8197876: zif_apc_add (php_apc.c:689)
==31961== 
==31961== Conditional jump or move depends on uninitialised value(s)
==31961==    at 0x81B1444: apc_new_interned_string (apc_string.c:109)
==31961==    by 0x81A02D4: apc_string_pmemcpy (apc_compile.c:283)
==31961==    by 0x81A054B: my_copy_zval (apc_compile.c:338)
==31961==    by 0x819FFC5: my_copy_zval_ptr (apc_compile.c:219)
==31961==    by 0x81A1A51: my_copy_hashtable_ex (apc_compile.c:925)
==31961==    by 0x81A05D4: my_copy_zval (apc_compile.c:349)
==31961==    by 0x81A1C52: apc_copy_zval (apc_compile.c:990)
==31961==    by 0x819E6A1: apc_cache_store_zval (apc_cache.c:1114)
==31961==    by 0x819E8A1: apc_cache_make_user_entry (apc_cache.c:1158)
==31961==    by 0x8197464: _apc_store (php_apc.c:610)
==31961==    by 0x81977AC: apc_store_helper (php_apc.c:669)
==31961==    by 0x8197876: zif_apc_add (php_apc.c:689)


This is because APC does not initialize its interned_string buffer in  apc_interned_strings_init() .Please, consider initializing the buffer to get rid of the warnings - may not be the worst idea for a string buffer. 

nixnutz@linux-0v4u:~/php-src/branches/PHP_5_4/ext/apc> svn diff
Index: apc_string.c
===================================================================
--- apc_string.c        (Revision 322504)
+++ apc_string.c        (Arbeitskopie)
@@ -198,6 +198,7 @@
     int count = APCG(shm_strings_buffer) / (sizeof(Bucket) + sizeof(Bucket*) * 2);
 
     apc_interned_strings_data = (apc_interned_strings_data_t*) apc_sma_malloc(APCG(shm_strings_buffer) TSRMLS_CC);
+    memset((char *)apc_interned_strings_data, 0, APCG(shm_strings_buffer));
 
     CREATE_LOCK(APCSG(lock));
 





Test script:
---------------
valgrind sapi/cli/php -d apc.enable_cli=1 -r '$tmp = array("foo" => "bar"); apc_add("tmp", $tmp); var_dump(apc_fetch("tmp")); '

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 [2012-01-21 04:55 UTC] rasmus@php.net
-Status: Open +Status: Feedback
 [2012-01-21 04:55 UTC] rasmus@php.net 
Looks right. You have commit karma for all of pecl. Just go ahead commit the fix.
 [2012-01-23 08:17 UTC] uw@php.net 
Automatic comment from SVN on behalf of uw
Revision: http://svn.php.net/viewvc/?view=revision&revision=322602
Log: Fix for bug #60821. Initialize buffer to avoid valgrind warnings.
 [2012-01-23 08:28 UTC] uw@php.net 
This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.

Done, http://news.php.net/php.pecl.cvs/17487 .
 [2012-01-23 08:28 UTC] uw@php.net
-Status: Feedback +Status: Closed -Assigned To: +Assigned To: uw
 
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