From: jeannielu at hotmail dot com
Operating system: Linux 2.6.16-22
PHP version: 5.1.6
PHP Bug Type: Reproducible crash
Bug description: seg fault during array_walk due to reallocated stack
Description:
------------
I reliably get a seg fault during execution of array_walk() in our web
application. Unfortunately, the seg fault is not reproducible with any
simpler test case.
gdb shows the death to be here:
#0 zend_call_function (fci=0xbfe8bcf0, fci_cache=0xbfe8bd14)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_execute_API.c:859
859 (*fci->params[i])->refcount++;
FYI, the call looks like this:
array_walk($current_set,
array($this, '_format_traffic_data'),
$dd
);
Where $current_set is a 2-D array of 10x5 elements, $dd another 2-D array
of 2x2 elements. Each element is a string of 10-30 characters. However, I
don't think the argument details are important.
Valgrind shows that zend_call_function died processing the third argument
because it referenced memory freed by zend_ptr_stack.h. See attached
backtrace.
Actual result:
--------------
gdb:
#0 zend_call_function (fci=0xbfe8bcf0, fci_cache=0xbfe8bd14)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_execute_API.c:859
#1 0x081bdb35 in php_array_walk (target_hash=0x90472cc,
userdata=0x85ebd6c, recursive=0)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/ext/standard/array.c:1099
#2 0x081bdeaf in zif_array_walk (ht=3, return_value=0x904b69c,
return_value_ptr=0x0, this_ptr=0x0, return_value_used=0)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/ext/standard/array.c:1159
#3 0x0826af4d in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe8cbd0)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:200
#4 0x0826a6f1 in execute (op_array=0x894b304) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#5 0x0826a928 in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe8df80)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:234
#6 0x0826a6f1 in execute (op_array=0x8b12e34) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#7 0x0826a928 in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe8f360)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:234
#8 0x0826a6f1 in execute (op_array=0x8ada67c) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#9 0x0826a928 in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe90280)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:234
#10 0x0826a6f1 in execute (op_array=0x8ac0bfc) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#11 0x0826a928 in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe92240)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:234
#12 0x0826a6f1 in execute (op_array=0x860b9e0) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#13 0x0826a928 in zend_do_fcall_common_helper_SPEC
(execute_data=0xbfe923b0)
at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:234
#14 0x0826a6f1 in execute (op_array=0x85f609c) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend_vm_execute.h:92
#15 0x0825471f in zend_execute_scripts (type=8, retval=Variable "retval"
is not available.
) at /usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/Zend/zend.c:1109
#16 0x0822029c in php_execute_script (primary_file=0xbfe947d4)
at /usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/main/main.c:1737
#17 0x082ce8ad in main (argc=5, argv=0xbfe94914) at
/usr/src/redhat/SOURCES/mazu/apache/php-5.1.6/sapi/cli/php_cli.c:1093
(gdb) print *fci->params[2]
$1 = (zval *) 0x39
valgrind:
==7352== LEAK SUMMARY:
==7352== definitely lost: 0 bytes in 0 blocks.
==7352== possibly lost: 1,088 bytes in 1 blocks.
==7352== still reachable: 49,274 bytes in 568 blocks.
==7352== suppressed: 0 bytes in 0 blocks.
==7352== Reachable blocks (those to which a pointer was found) are not
shown.
==7352== To see them, rerun with: --show-reachable=yes
==7313== Invalid read of size 4
==7313== at 0x81BDAF6: php_array_walk (array.c:1090)
==7313== by 0x81BDEAE: zif_array_walk (array.c:1159)
==7313== by 0x826AF4C: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:200)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== Address 0x437A678 is 80 bytes inside a block of size 268 free'd
==7313== at 0x4005997: realloc (vg_replace_malloc.c:306)
==7313== by 0x82406C3: _erealloc (zend_alloc.c:388)
==7313== by 0x82906D4: zend_send_by_var_helper_SPEC_CV
(zend_ptr_stack.h:99)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
==7313== by 0x826A927: zend_do_fcall_common_helper_SPEC
(zend_vm_execute.h:234)
==7313== by 0x826A6F0: execute (zend_vm_execute.h:92)
--
Edit bug report at http://bugs.php.net/?id=38956&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=38956&r=trysnapshot44
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=38956&r=trysnapshot52
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=38956&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=38956&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=38956&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=38956&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=38956&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=38956&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=38956&r=support
Expected behavior: http://bugs.php.net/fix.php?id=38956&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=38956&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=38956&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=38956&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=38956&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=38956&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=38956&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=38956&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=38956&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=38956&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=38956&r=mysqlcfg
