Edit report at https://bugs.php.net/bug.php?id=61046&edit=1
ID: 61046
Updated by: laruence@php.net
Reported by: nikic@php.net
Summary: Segfault when memory limit is hit while copying hash
table
Status: Feedback
Type: Bug
Package: Reproducible crash
PHP Version: 5.4.0RC7
Block user comment: N
Private report: N
New Comment:
another way to fix this is promote the ht point assignment in ctor(list blow),
but there is still a chance that alloc failed when try to alloc memory for ht.
so I still think the fix I attached is the better one.
diff --git a/Zend/zend_variables.c b/Zend/zend_variables.c
index 25a66a1..bb6927a 100644
--- a/Zend/zend_variables.c
+++ b/Zend/zend_variables.c
@@ -134,9 +134,9 @@ ZEND_API void _zval_copy_ctor_func(zval *zvalue
ZEND_FILE_LINE_DC)
return; /* do nothing */
}
ALLOC_HASHTABLE_REL(tmp_ht);
+ zvalue->value.ht = tmp_ht;
zend_hash_init(tmp_ht,
zend_hash_num_elements(original_ht), NULL, ZVAL_PTR_DTOR, 0);
zend_hash_copy(tmp_ht, original_ht,
(copy_ctor_func_t) zval_add_ref, (void *) &tmp, sizeof(zval *));
- zvalue->value.ht = tmp_ht;
}
break;
case IS_OBJECT:
Previous Comments:
------------------------------------------------------------------------
[2012-12-20 15:08:30] laruence@php.net
quick fix attached, could you please verify it?
------------------------------------------------------------------------
[2012-12-20 15:07:27] laruence@php.net
The following patch has been added/updated:
Patch Name: bug61046.patch
Revision: 1356016047
URL: https://bugs.php.net/patch-display.php?bug=61046&patch=bug61046.patch&revision=1356016047
------------------------------------------------------------------------
[2012-12-20 11:18:02] arrtedone at gmail dot com
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.
------------------------------------------------------------------------
[2012-02-10 18:08:37] rasmus@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] jpauli@php.net
Notice that I only reproduce with memory_limit set to accurate 512k , not 500k as
in bug text, nor even 511k
------------------------------------------------------------------------
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the rest of the comments, please view the bug report online at
https://bugs.php.net/bug.php?id=61046
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