Bug #70360 [Com]: Segmentation fault for every request

From: Date: Fri, 28 Aug 2015 10:11:30 +0000
Subject: Bug #70360 [Com]: Segmentation fault for every request
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-195586@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=70360&edit=1

 ID:                 70360
 Comment by:         steve at stephenorr dot co dot uk
 Reported by:        atippett at gmail dot com
 Summary:            Segmentation fault for every request
 Status:             Open
 Type:               Bug
 Package:            opcache
 Operating System:   Linux fenrir 3.16.0-4-amd64 #1
 PHP Version:        5.6.12
 Block user comment: N
 Private report:     N

 New Comment:

Same issue for me on PHP 5.6.12-1+deb.sury.org~vivid+1 (as provided in ondrej PPA on Ubuntu).

Disabling opcache initially appeared to resolve the problem, but it looks like my actual issue was
that I also had the xcache extension enabled, and the two were conflicting.

Uninstalling xcache and re-enabling opcache seems to work.


Previous Comments:
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[2015-08-26 06:37:41] atippett at gmail dot com

changing to package opcache

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[2015-08-26 06:35:39] atippett at gmail dot com

Please advice:

After much poking, turning off opcache (7.0.4) fixes the issues.  It's terrible hard to
diagnosis what's going on and any recommendations are welcome.  The code runs fine after an
apache2ctl restart for sometimes a 1/2 day or so but if we stress test the system with a lots of
connections we can reproduce a segmentation fault when opcache is on.  Other sites under the same
webserver continue to work but any access to the url we stress test produces a core dump on every
request until we restart apache.  We've tried to narrow down what code is causing it but have
been unsuccessful at finding a code example that we can pass on.  Any recommendations?

------------------------------------------------------------------------
[2015-08-26 06:35:34] atippett at gmail dot com

Please advice:

After much poking, turning off opcache (7.0.4) fixes the issues.  It's terrible hard to
diagnosis what's going on and any recommendations are welcome.  The code runs fine after an
apache2ctl restart for sometimes a 1/2 day or so but if we stress test the system with a lots of
connections we can reproduce a segmentation fault when opcache is on.  Other sites under the same
webserver continue to work but any access to the url we stress test produces a core dump on every
request until we restart apache.  We've tried to narrow down what code is causing it but have
been unsuccessful at finding a code example that we can pass on.  Any recommendations?

------------------------------------------------------------------------
[2015-08-25 17:56:31] requinix@php.net

Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves. 

A proper reproducing script starts with <?php and ends with ?>,
is max. 10-20 lines long and does not require any external 
resources such as databases, etc. If the script requires a 
database to demonstrate the issue, please make sure it creates 
all necessary tables, stored procedures etc.

Please avoid embedding huge scripts into the report.



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[2015-08-25 17:41:09] atippett at gmail dot com

Description:
------------
Segmentation fault.

version: PHP 5.6.9-0+deb8u1 (cli) (built: Jun  5 2015 11:03:27) 


Any help on how to diagnose this would be appreciated.

Actual result:
--------------
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007fe60d50658a in gc_remove_from_buffer (root=0x7fe5fdf7b030) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_gc.h:190
190     /tmp/buildd/php5-5.6.9+dfsg/Zend/zend_gc.h: No such file or directory.
(gdb) bt
#0  0x00007fe60d50658a in gc_remove_from_buffer (root=0x7fe5fdf7b030) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_gc.h:190
#1  gc_remove_zval_from_buffer (zv=zv@entry=0x7fe5fdf7b078) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_gc.c:260
#2  0x00007fe60d4d5018 in i_zval_ptr_dtor (zval_ptr=0x7fe5fdf7b078) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_execute.h:78
#3  _zval_ptr_dtor (zval_ptr=<optimized out>) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_execute_API.c:424
#4  0x00007fe60d4f43b8 in zend_hash_destroy (ht=0x7fe617242ac8) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_hash.c:548
#5  0x00007fe60d4e4d6b in _zval_dtor_func (zvalue=0x7fe5fdf7b078) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_variables.c:45
#6  0x00007fe60d594610 in _zval_dtor (zvalue=<optimized out>) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_variables.h:35
#7  i_zval_ptr_dtor (zval_ptr=<optimized out>) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_execute.h:79
#8  zend_vm_stack_clear_multiple (nested=<optimized out>) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_execute.h:308
#9  zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a96478) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:650
#10 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a96478) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#11 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a96478) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#12 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#13 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#14 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a962e0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#15 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a962e0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#16 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a962e0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#17 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#18 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#19 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a96118) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#20 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a96118) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#21 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a96118) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#22 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#23 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#24 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a95fd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#25 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a95fd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#26 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a95fd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#27 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#28 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#29 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a95ee8) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#30 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a95ee8) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#31 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a95ee8) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#32 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#33 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#34 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a95d30) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#35 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a95d30) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#36 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a95d30) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#37 0x00007fe6025ac18d in nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1056
#38 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#39 0x00007fe60d594b1e in zend_do_fcall_common_helper_SPEC (execute_data=0x7fe616a95bd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:592
#40 0x00007fe60d523020 in execute_ex (execute_data=0x7fe616a95bd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_vm_execute.h:363
#41 0x00007fe60d4d4cf8 in dtrace_execute_ex (execute_data=0x7fe616a95bd0) at
/tmp/buildd/php5-5.6.9+dfsg/Zend/zend_dtrace.c:73
#42 0x00007fe6025ac402 in nr_php_execute_file () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:889
#43 nr_php_execute_enabled () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:921
#44 0x00007fe6025ac982 in nr_php_execute () at
/home/hudson/slave-workspace/workspace/PHP_Release_Agent/label/centos5-64-nrcamp/agent/php_execute.c:1167
#45 0x00007fe60d4e77f0 in zend_execute_scripts (type=-34099080, type@entry=8, retval=0x7fe600000000,
retval@entry=0x0, file_count=231379392, file_count@entry=3)
    at /tmp/buildd/php5-5.6.9+dfsg/Zend/zend.c:1341
#46 0x00007fe60d483560 in php_execute_script (primary_file=primary_file@entry=0x7ffc9cbfda60) at
/tmp/buildd/php5-5.6.9+dfsg/main/main.c:2597
#47 0x00007fe60d5961ca in php_handler (r=<optimized out>) at
/tmp/buildd/php5-5.6.9+dfsg/sapi/apache2handler/sapi_apache2.c:667
#48 0x00007fe614fab290 in ap_run_handler (r=r@entry=0x7fe6150900a0) at config.c:169
#49 0x00007fe614fab7d9 in ap_invoke_handler (r=0x7fe6150900a0) at config.c:433
#50 0x00007fe614fc1672 in ap_process_async_request (r=0x7fe6150900a0) at http_request.c:317
#51 0x00007fe614fc1810 in ap_process_request (r=0x7fe6150900a0) at http_request.c:363
#52 0x00007fe614fbe112 in ap_process_http_sync_connection (c=0x7fe6150a1290) at http_core.c:190
#53 ap_process_http_connection (c=0x7fe6150a1290) at http_core.c:231
#54 0x00007fe614fb4b00 in ap_run_process_connection (c=0x7fe6150a1290) at connection.c:41
#55 0x00007fe60deb87ba in child_main (child_num_arg=-34099080) at prefork.c:704
#56 0x00007fe60deb8a01 in make_child (s=0x7fe6151a8de0, slot=65) at prefork.c:800
#57 0x00007fe60deb9667 in perform_idle_server_maintenance (p=<optimized out>) at prefork.c:902
#58 prefork_run (_pconf=0x7fe6151f1f38 <ap_server_conf>, plog=0x7ffc9cbfdecc,
s=0x7ffc9cbfded0) at prefork.c:1090
#59 0x00007fe614f90e7e in ap_run_mpm (pconf=0x7fe6151e0028, plog=0x7fe6151ae028, s=0x7fe6151a8de0)
at mpm_common.c:94
#60 0x00007fe614f8a3c3 in main (argc=3, argv=0x7ffc9cbfe1b8) at main.c:777



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