Bug #72179 [Asn->Fbk]: Segfault in gc_possible_root on CLI
Edit report at https://bugs.php.net/bug.php?id=72179&edit=1
ID: 72179
Updated by: cmb@php.net
Reported by: webmaster at tom-geiger dot de
Summary: Segfault in gc_possible_root on CLI
-Status: Assigned
+Status: Feedback
Type: Bug
Package: Reproducible crash
Operating System: Ubuntu 16.10
PHP Version: 7.0.12
-Assigned To: laruence
+Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
Is this still an issue with any of the actively supported PHP
versions[1]?
[1] <https://www.php.net/supported-versions.php>
Previous Comments:
------------------------------------------------------------------------
[2016-10-20 09:38:32] webmaster at tom-geiger dot de
Issue still occurs with PHP 7.0.12.
I managed to work around the issue a bit more. The following pseudo code describes the issue
further:
--- Segfaulting code ---
whie (true) {
fetchEventFromDatabase();
handleEvent(); // Somewhere here the GC starts and segfaults
}
--- End Code ---
Disabling GC:
--- NOT- Segfaulting code ---
gc_disable();
whie (true) {
fetchEventFromDatabase();
handleEvent(); // GC never starts, so no segfault
--- End Code ---
Optimized workaround:
--- SOMETIMES- Segfaulting code ---
define(DO_GC, 50);
gc_disable();
whie (true) {
fetchEventFromDatabase();
handleEvent();
if(rand(1, DO_GC) == DO_GC) {
gc_collect_cycles(); // This segfaults depending on DO_GC
}
--- End Code ---
In my environment, having DO_GC < 20 will keep the script from segfaulting.
Above 20 I will have segfaults when executing gc_collect_cycles().
Ths leads me to assume that gc_collect_cycles() will segfault depending on the amount of cycles it
has to collect.
I hope this helps to further isolate the issue.
------------------------------------------------------------------------
[2016-07-20 20:05:28] ccovey14 at gmail dot com
I am still seeing this in 7.0.8. We see it in our functional test suite, always in the same test,
although running just the test it fails on passes as expected. I can also confirm calling gc_disable
does in fact allow the test suite to pass. gdb backtrace and php modules below.
#gdb Backtrace
#0 gc_possible_root (ref=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_gc.c:262
#1 0x0000000000575d14 in var_destroy (var_hashx=<value optimized out>) at
/usr/src/debug/php-7.0.8/ext/standard/var_unserializer.c:160
#2 0x0000000000564848 in zif_unserialize (execute_data=<value optimized out>,
return_value=0x7f7524e1a530) at /usr/src/debug/php-7.0.8/ext/standard/var.c:1087
#3 0x00000000005d5029 in dtrace_execute_internal (execute_data=<value optimized out>,
return_value=<value optimized out>)
at /usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:107
#4 0x000000000065b522 in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e1a4d0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:844
#5 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#6 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e1a4d0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#7 0x000000000066867d in ZEND_INCLUDE_OR_EVAL_SPEC_CV_HANDLER (execute_data=0x7f7524e1a0a0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:29337
#8 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#9 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e1a0a0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#10 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e193a0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#11 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#12 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e193a0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#13 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e19220) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#14 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#15 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e19220) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#16 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e18d50) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#17 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#18 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e18d50) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#19 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e18a50) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#20 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#21 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e18a50) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#22 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e18610) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#23 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#24 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e18610) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#25 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e18390) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#26 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#27 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e18390) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#28 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e181d0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#29 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#30 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e181d0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#31 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e176e0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#32 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#33 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e176e0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#34 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e17650) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#35 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#36 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e17650) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#37 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e16ea0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#38 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#39 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e16ea0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#40 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e16300) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#41 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#42 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e16300) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#43 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e158a0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#44 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#45 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e158a0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#46 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e152c0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
---Type <return> to continue, or q <return> to quit---
#47 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#48 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e152c0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#49 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e14ce0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#50 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#51 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e14ce0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#52 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e136b0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#53 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#54 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e136b0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#55 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e13290) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#56 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#57 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e13290) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#58 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e131a0) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#59 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#60 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e131a0) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#61 0x000000000065b39a in ZEND_DO_FCALL_SPEC_HANDLER (execute_data=0x7f7524e13030) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:800
#62 0x00000000006231d0 in execute_ex (ex=<value optimized out>) at
/usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:417
#63 0x00000000005d516e in dtrace_execute_ex (execute_data=0x7f7524e13030) at
/usr/src/debug/php-7.0.8/Zend/zend_dtrace.c:83
#64 0x000000000067689b in zend_execute (op_array=0x7f7524e85000, return_value=<value optimized
out>) at /usr/src/debug/php-7.0.8/Zend/zend_vm_execute.h:458
#65 0x00000000005e3b03 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at
/usr/src/debug/php-7.0.8/Zend/zend.c:1427
#66 0x0000000000585180 in php_execute_script (primary_file=0x7ffdbd74a970) at
/usr/src/debug/php-7.0.8/main/main.c:2494
#67 0x000000000067ab9a in do_cli (argc=9, argv=0x1e1bd50) at
/usr/src/debug/php-7.0.8/sapi/cli/php_cli.c:974
#68 0x000000000067b39a in main (argc=9, argv=0x1e1bd50) at
/usr/src/debug/php-7.0.8/sapi/cli/php_cli.c:1344
# PHP modules installed
[PHP Modules]
apc
apcu
bcmath
bz2
calendar
Core
ctype
curl
date
dom
exif
fileinfo
filter
ftp
gd
gettext
hash
iconv
igbinary
imagick
imap
intl
json
ldap
libxml
mbstring
mongodb
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
pdo_sqlite
Phar
posix
readline
redis
Reflection
session
shmop
SimpleXML
soap
sockets
solr
SPL
sqlite3
standard
sysvmsg
sysvsem
sysvshm
tokenizer
wddx
xml
xmlreader
xmlwriter
xsl
Zend OPcache
zip
zlib
[Zend Modules]
Zend OPcache
------------------------------------------------------------------------
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