Bug #72179 [Fbk->NoF]: Segfault in gc_possible_root on CLI

Edit report at https://bugs.php.net/bug.php?id=72179&edit=1 ID: 72179 Updated by: php-bugs@lists.php.net Reported by: webmaster at tom-geiger dot de Summary: Segfault in gc_possible_root on CLI -Status: Feedback +Status: No Feedback Type: Bug Package: Reproducible crash Operating System: Ubuntu 16.10 PHP Version: 7.0.12 Assigned To: cmb Private report: N New Comment: No feedback was provided. The bug is being suspended because we assume that you are no longer experiencing the problem. If this is not the case and you are able to provide the information that was requested earlier, please do so and change the status of the bug back to "Re-Opened". Thank you. Previous Comments: ------------------------------------------------------------------------ [2021-05-28 14:23:40] cmb@php.net Is this still an issue with any of the actively supported PHP versions[1]? [1] <https://www.php.net/supported-versions.php> ------------------------------------------------------------------------ [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 ------------------------------------------------------------------------ The remainder of the comments for this report are too long. 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