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Bug #25738 Long Scripts Consistently Segfault
Submitted: 2003-10-02 22:13 UTC Modified: 2003-10-03 19:20 UTC
Avg. Score:4.5 ± 0.9
Reproduced:4 of 4 (100.0%)
Same Version:0 (0.0%)
Same OS:0 (0.0%)
From: ohornoiu at bellevuechristian dot org Assigned:
Status: Closed Package: Scripting Engine problem
PHP Version: 4.3.3 OS: Mac OS X 10.2.6+
Private report: No CVE-ID: None
 [2003-10-02 22:13 UTC] ohornoiu at bellevuechristian dot org


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 [2003-10-03 15:46 UTC]
Thank you for this bug report. To properly diagnose the problem, we
need a backtrace to see what is happening behind the scenes. To
find out how to generate a backtrace, please read

Once you have generated a backtrace, please submit it to this bug
report and change the status back to "Open". Thank you for helping
us make PHP better.

NOTE: See also bug #22231, bug #22367, and bug #22510.

 [2003-10-03 16:14 UTC] mark dot meredith at shaw dot ca
Here is the backtrace as a result of crashing the simpler, 
$x = 1; done 10,000 times script as per the original 
reported bug #25394...

#0  0x900048b0 in malloc ()
(gdb) bt
#0  0x900048b0 in malloc ()
#1  0x000f0bb4 in zend_hash_add_or_update (ht=0x139c14, 
arKey=0x3773a8 "x", nKeyLength=2, pData=0xbff80184, 
nDataSize=4, pDest=0xbff80168, flag=1) at /Users/markmere/
#2  0x000fe230 in zend_fetch_var_address (opline=0x424028, 
Ts=0xbff801e0, type=1) at /Users/markmere/Sources/php4-
#3  0x00100a88 in execute (op_array=0x375f28) at /Users/
#4  0x000e9f94 in zend_execute_scripts (type=8, retval=0x0, 
file_count=3) at /Users/markmere/Sources/php4-snapshot/
#5  0x0009c6b8 in php_execute_script 
(primary_file=0xbffff760) at /Users/markmere/Sources/php4-
#6  0x0010a744 in main (argc=2, argv=0xbffffcc0) at /Users/
#7  0x00001a50 in _start (argc=2, argv=0xbffffcc0, 
envp=0xbffffccc) at /SourceCache/Csu/Csu-45/crt.c:267
#8  0x000018d0 in start ()

... I generated this backtrace using the latest snapshot.

Bug #29394 is just a test case representing any script long 
enough to tickle the crasher. It is just $x = 1; done 
around 10,000 times. On my Mac, it takes 8041 assignments. 
The crasher still goes if the script is broken up into 
multiple include()'s.
 [2003-10-03 17:25 UTC]
Darwin aphrodite 6.6 Darwin Kernel Version 6.6:
Thu May  1 21:48:54 PDT 2003;
Power Macintosh powerpc

latest PHP_4_3 branch, a vanilla configure, and a
script containing approx 16000 $x=1; assignments, I get

Program received signal EXC_BAD_ACCESS, Could not access memory.
execute (op_array=0x460780) at /Users/wez/src/php4.3cvs/Zend/zend_execute.c:1027
1027            EX(Ts) = (temp_variable *) do_alloca(sizeof(temp_variable)*op_array->T);
(gdb) bt
#0  execute (op_array=0x460780) at /Users/wez/src/php4.3cvs/Zend/zend_execute.c:1027
#1  0x000d6b14 in zend_execute_scripts (type=0, retval=0x0, file_count=3) at /Users/wez/src/php4.3cvs/Zend/zend.c:885
#2  0x000ab9e8 in php_execute_script (primary_file=0x0) at /Users/wez/src/php4.3cvs/main/main.c:1732
#3  0x000e9f88 in main (argc=3, argv=0xbffffd60) at /Users/wez/src/php4.3cvs/sapi/cli/php_cli.c:819
#4  0x000023e4 in _start (argc=3, argv=0xbffffd60, envp=0xbffffd70) at /SourceCache/Csu/Csu-45/crt.c:267
#5  0x00002264 in start ()

My guess is that we are overflowing either the stack
or the Ts storage space since the scope of the function
"never" ends.

 [2003-10-03 17:36 UTC]
Sounds like yet another alloca() problem to me.
Could try this patch and tell me what would actually happen.

 [2003-10-03 17:58 UTC]
Seems to work for me.
 [2003-10-03 19:18 UTC] mark dot meredith at shaw dot ca
Beautiful. The patch seems to work for me as well. I tried 
with over 100,000 assignments with no problems.
 [2003-10-03 19:20 UTC]
This bug has been fixed in CVS.

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