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Bug #25369 building 64K arrays of 64K elements segfaults
Submitted: 2003-09-02 18:28 UTC Modified: 2003-09-02 23:48 UTC
From: moregan at flr dot follett dot com Assigned:
Status: Closed Package: Reproducible crash
PHP Version: 4.3.3 OS: RedHat8 + Windows 2000
Private report: No CVE-ID: None
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 [2003-09-02 18:28 UTC] moregan at flr dot follett dot com
Description:
------------
(This arose from working with script from the now-closed bug 23333.  I accidentally put material intended for 23333 into 25275, but this now seems to me to be a separate bug.)

A CLI script that builds an array of 65536 numbers and then makes 65536 copies segfaults.  True for /php4-STABLE-200309020330 on RedHat 8 and for the binary from php4-win32-STABLE-200309022030.zip on Windows 2000.

The example may seem contrived, but I'm hoping that this is one of the causes of a thorny heap corruption problem we're seeing.

Reproduce code:
---------------
<?php

$elements = 65536;

$big = array();
$test = array();

for($i=0; $i < $elements; $i++) {
    $big[$i] = $i;
}

for($i=0; $i < $elements; $i++) {
    $test[$i] = $big;
}

?>

If you change $elements to 65535 then there's no segfault.

Expected result:
----------------
nothing

Actual result:
--------------
(gdb) bt full
#0  0x080c6769 in php_strlcpy (dst=0x8135ac0 "-", src=0x5a5a5a5a <Address 0x5a5a5a5a out of bounds>, siz=1024)
    at /home/moregan/php4-STABLE-200309020330/main/strlcpy.c:58
        d = 0x8135ac0 "-"
        s = 0x5a5a5a5a <Address 0x5a5a5a5a out of bounds>
        n = 1023
#1  0x080bd020 in php_error_cb (type=8, error_filename=0x5a5a5a5a <Address 0x5a5a5a5a out of bounds>, error_lineno=35,
    format=0x812ad40 "Use of undefined constant %s - assumed '%s'", args=0xbfffb9c8 "?\037\027\b?\037\027\b?\037\027\b\006")
    at /home/moregan/php4-STABLE-200309020330/main/main.c:615
        buffer = 0x816a4ec "Use of undefined constant STDERR - assumed 'STDERR'"
        buffer_len = 51
        display = 1
#2  0x080ee343 in zend_error (type=8, format=0x812ad40 "Use of undefined constant %s - assumed '%s'")
    at /home/moregan/php4-STABLE-200309020330/Zend/zend.c:751
        args = 0xbfffb9c8 "?\037\027\b?\037\027\b?\037\027\b\006"
        params = (struct _zval_struct ***) 0x0
        retval = (struct _zval_struct *) 0xbfffb9c8
        z_error_type = (struct _zval_struct *) 0x81285c0
        z_error_message = (struct _zval_struct *) 0x81716cc
        z_error_filename = (struct _zval_struct *) 0xbfffb9b4
        z_error_lineno = (struct _zval_struct *) 0x7
        z_context = (struct _zval_struct *) 0x8007272
        error_filename = 0x5a5a5a5a <Address 0x5a5a5a5a out of bounds>
        error_lineno = 35
        orig_user_error_handler = (struct _zval_struct *) 0x7
#3  0x080ffa0c in execute (op_array=0x8171b2c) at /home/moregan/php4-STABLE-200309020330/Zend/zend_execute.c:1989
        execute_data = {opline = 0x8171260, function_state = {function_symbol_table = 0x0, function = 0x8171b2c, reserved = {
      0x80fabde, 0x8171fbc, 0x5a9b0765, 0x1c}}, fbc = 0x0, ce = 0x0, object = {ptr = 0x0}, Ts = 0xbfffb9d0,
  original_in_execution = 1 '\001', op_array = 0x8171b2c, prev_execute_data = 0xbfffbe20}
#4  0x080fe633 in execute (op_array=0x816a464) at /home/moregan/php4-STABLE-200309020330/Zend/zend_execute.c:1660
        calling_symbol_table = (struct _hashtable *) 0x813a14c
        original_return_value = (struct _zval_struct **) 0xbfffbea4
        return_value_used = 0
        execute_data = {opline = 0x816e850, function_state = {function_symbol_table = 0x81715c4, function = 0x8171b2c, reserved = {
      0x10001, 0x4000000, 0x0, 0x0}}, fbc = 0x8171b2c, ce = 0x0, object = {ptr = 0x8170a04}, Ts = 0xbfffbc20,
  original_in_execution = 0 '\0', op_array = 0x816a464, prev_execute_data = 0x0}
#5  0x080ee81c in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /home/moregan/php4-STABLE-200309020330/Zend/zend.c:885
        files = 0xbfffbed4 ""
        i = 1
        file_handle = (struct _zend_file_handle *) 0xbfffe170
        orig_op_array = (struct _zend_op_array *) 0x0
        local_retval = (struct _zval_struct *) 0x0
#6  0x080bf239 in php_execute_script (primary_file=0xbfffe170) at /home/moregan/php4-STABLE-200309020330/main/main.c:1723
        orig_bailout = {{__jmpbuf = {1108517584, 1073815584, -1073749500, -1073749576, -1073749984, 135281170},
    __mask_was_saved = 0, __saved_mask = {__val = {0 <repeats 32 times>}}}}
        orig_bailout_set = 1 '\001'
        prepend_file_p = (struct _zend_file_handle *) 0x0
        append_file_p = (struct _zend_file_handle *) 0x0
        prepend_file = {type = 0 '\0', filename = 0x0, opened_path = 0x0, handle = {fd = 0, fp = 0x0}, free_filename = 0 '\0'}
        append_file = {type = 0 '\0', filename = 0x0, opened_path = 0x0, handle = {fd = 0, fp = 0x0}, free_filename = 0 '\0'}
        old_cwd = 0xbfffbee0 ""
        old_primary_file_path = 0x0
        retval = 0
#7  0x08104108 in main (argc=1, argv=0xbfffe204) at /home/moregan/php4-STABLE-200309020330/sapi/cli/php_cli.c:819
        orig_bailout = {{__jmpbuf = {0, 0, 0, 0, 0, 0}, __mask_was_saved = 0, __saved_mask = {__val = {0 <repeats 32 times>}}}}
        orig_bailout_set = 0 '\0'
        exit_status = 0
        c = -1
        file_handle = {type = 2 '\002', filename = 0x812bb4b "-", opened_path = 0x0, handle = {fd = 1108505024, fp = 0x421271c0},
  free_filename = 0 '\0'}
        behavior = 1
        orig_optind = 1
        orig_optarg = 0x0
        arg_free = 0xbffffbb1 "./sapi/cli/php"
        arg_excp = (char **) 0xbfffe204
        script_file = 0x0
        global_vars = {head = 0x0, tail = 0x0, size = 4, count = 0, dtor = 0, persistent = 0 '\0', traverse_ptr = 0xbfffe204}
        interactive = 0
        module_started = 1
        lineno = 0
        exec_direct = 0x0
        param_error = 0x0
        hide_argv = 0
#8  0x420158d4 in __libc_start_main () from /lib/i686/libc.so.6
No symbol table info available.


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 [2003-09-02 19:44 UTC] helly@php.net
64K * 64K = 2^32. Your system couldn't address that range even if we were talking about bytes. However you should have seen an error instead of the SEGV.
 [2003-09-02 23:48 UTC] sniper@php.net
That backtrace is definately not the correct one,
this one is:

(gdb) bt
#0  __libc_free (mem=0x401aa014) at malloc.c:3005
#1  0x80d7c02 in zend_hash_destroy (ht=0x8141014) at /usr/src/web/php/php4_3/Zend/zend_hash.c:560
#2  0x80d2c88 in _zval_dtor (zvalue=0x814104c) at /usr/src/web/php/php4_3/Zend/zend_variables.c:51
#3  0x80cc118 in _zval_ptr_dtor (zval_ptr=0x8a46838) at /usr/src/web/php/php4_3/Zend/zend_execute_API.c:291
#4  0x80d7b98 in zend_hash_destroy (ht=0x814a28c) at /usr/src/web/php/php4_3/Zend/zend_hash.c:553
#5  0x80d2c88 in _zval_dtor (zvalue=0x814a2fc) at /usr/src/web/php/php4_3/Zend/zend_variables.c:51
#6  0x80cc118 in _zval_ptr_dtor (zval_ptr=0x814a2d0) at /usr/src/web/php/php4_3/Zend/zend_execute_API.c:291
#7  0x80d7b98 in zend_hash_destroy (ht=0x811ee4c) at /usr/src/web/php/php4_3/Zend/zend_hash.c:553
#8  0x80cbe91 in shutdown_executor () at /usr/src/web/php/php4_3/Zend/zend_execute_API.c:186
#9  0x80d3aef in zend_deactivate () at /usr/src/web/php/php4_3/Zend/zend.c:665
#10 0x80aecca in php_request_shutdown (dummy=0x0) at /usr/src/web/php/php4_3/main/main.c:998
#11 0x80eab47 in main (argc=2, argv=0xbffff8f4) at /usr/src/web/php/php4_3/sapi/cli/php_cli.c:870
#12 0x400709cb in __libc_start_main (main=0x80ea1b8 <main>, argc=2, argv=0xbffff8f4, init=0x80593fc <_init>, 
    fini=0x80eaf74 <_fini>, rtld_fini=0x4000aea0 <_dl_fini>, stack_end=0xbffff8ec)
    at ../sysdeps/generic/libc-start.c:92

And this does NOT happen with latest CVS of PHP 5.
(feel free to prove me wrong)

 
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