Edit report at https://bugs.php.net/bug.php?id=61046&edit=1
ID: 61046
Comment by: arrtedone at gmail dot com
Reported by: ni...@php.net
Summary: Segfault when memory limit is hit while copying hash
table
Status: Open
Type: Bug
Package: Reproducible crash
PHP Version: 5.4.0RC7
Block user comment: N
Private report: N
New Comment:
Description:
------------
Same here, reproducable, but with memory limit set to 128M (note that i am not
using the provided test script, it crached randomly)
Test script:
-------------
-
System information :
OS : Fedora 17 Linux nask0 3.6.10-2.fc17.x86_64 #1 SMP Tue Dec 11 18:07:34 UTC
2012 x86_64
PHP version 5.4.9 :
PHP API : 20100412
PHP Extension : 20100525
Zend Extension : 220100525
Zend Extension Build : API220100525,NTS
PHP Extension Build : API20100525,NTS
Thread Safety: disabled
Zend Signal Handling: disabled
Zend Memory Manager: enabled
Apache Version: Apache/2.2.22 (Fedora) DAV/2 PHP/5.4.9
Apache API Version : 20051115
GDB backtrace :
---------------
Program received signal SIGSEGV, Segmentation fault.
zend_mm_remove_from_free_list (heap=0x7f75283c10d0, mm_block=0x7f752a24b3f8) at
/usr/src/debug/php-5.4.9/Zend/zend_alloc.c:833
833 if (UNEXPECTED(prev->next_free_block != mm_block) ||
UNEXPECTED(next->prev_free_block != mm_block)) {
(gdb) continue
Continuing.
Program terminated with signal SIGSEGV, Segmentation fault.
The program no longer exists.
Previous Comments:
------------------------------------------------------------------------
[2012-02-10 18:08:37] ras...@php.net
Same here. Reproducable on 64-bit Linux with memory_limit set to "512k".
The segfault is here:
zend_mm_remove_from_free_list (heap=0xf71730, mm_block=0x7ffff7fae1c8) at
/home/rasmus/php-src/branches/PHP_5_4/Zend/zend_alloc.c:805
805 ZEND_MM_CHECK_TREE(mm_block);
(gdb) p *mm_block
$2 = {info = {_size = 16400, _prev = 57}, prev_free_block = 0x7ffff7fae1c8,
next_free_block = 0x7ffff7fae1c8, parent = 0x0, child = {0x0, 0x0}}
Note that parent is NULL there and ZEND_MM_CHECK_TREE tries to dereference
*parent
------------------------------------------------------------------------
[2012-02-10 17:46:09] jpa...@php.net
Notice that I only reproduce with memory_limit set to accurate 512k , not 500k
as
in bug text, nor even 511k
------------------------------------------------------------------------
[2012-02-10 17:34:21] jpa...@php.net
What I can say :
- I dont reproduce on 5.3.10
- For 5.4, disabling ZendMM with USE_ZEND_ALLOC=0 makes the segfault disappear
- For 5.4, changing the ZendMM segment size with ZEND_MM_SEG_SIZE={val} makes
the
segfault disappear, I havent tested all the possible values for SEG_SIZE.
As a reminder, ZendMM default SEG_SIZE is set to 256k
------------------------------------------------------------------------
[2012-02-10 17:31:28] ni...@php.net
GDB Stacktrace:
#0 zend_mm_remove_from_free_list (heap=0x88da8d8, mm_block=0xb7fc5308)
at /home/nikic/dev/php-src-git/Zend/zend_alloc.c:805
#1 0x083ad608 in _zend_mm_free_int (heap=0x88da8d8, p=0xb7fc52f0)
at /home/nikic/dev/php-src-git/Zend/zend_alloc.c:2101
#2 0x083cd657 in destroy_op_array (op_array=0x8a5d4c8, tsrm_ls=0x88d9050)
at /home/nikic/dev/php-src-git/Zend/zend_opcode.c:380
#3 0x083cd777 in zend_function_dtor (function=0x8a5d4c8)
at /home/nikic/dev/php-src-git/Zend/zend_opcode.c:124
#4 0x083e49ae in zend_hash_apply_deleter (ht=0x88dae70, p=0x8a5d498)
at /home/nikic/dev/php-src-git/Zend/zend_hash.c:650
#5 0x083e63b1 in zend_hash_reverse_apply (ht=0x88dae70,
apply_func=0x83c7310 <clean_non_persistent_function>, tsrm_ls=0x88d9050)
at /home/nikic/dev/php-src-git/Zend/zend_hash.c:804
#6 0x083c7ecb in shutdown_executor (tsrm_ls=0x88d9050)
at /home/nikic/dev/php-src-git/Zend/zend_execute_API.c:304
#7 0x083d7c11 in zend_deactivate (tsrm_ls=0x88d9050)
at /home/nikic/dev/php-src-git/Zend/zend.c:934
#8 0x0836be33 in php_request_shutdown (dummy=0x0)
at /home/nikic/dev/php-src-git/main/main.c:1782
#9 0x0848d723 in do_cli (argc=4, argv=0xbffff3b4, tsrm_ls=0x88d9050)
at /home/nikic/dev/php-src-git/sapi/cli/php_cli.c:1169
#10 0x0806eaa3 in main (argc=4, argv=0xbffff3b4)
at /home/nikic/dev/php-src-git/sapi/cli/php_cli.c:1356
------------------------------------------------------------------------
[2012-02-10 17:28:02] ni...@php.net
Description:
------------
The attached test script triggers a segfault. It happens during the shutdown
after the memory limit is reached in the byRef($array) line.
Test script:
---------------
<?php
function byRef(&$ref) {}
ini_set('memory_limit', '500k');
$array = array_fill(0, 2000, '*');
$ref = $array;
byRef($array);
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=61046&edit=1
