#50265 [Fbk->Opn]: endless loop waiting for child process

ID: 50265 User updated by: mg at fork dot pl Reported By: mg at fork dot pl -Status: Feedback +Status: Open Bug Type: CGI related Operating System: Linux PHP Version: 5.2.11 New Comment: My previous comment shows state BEFORE the problem hits. Many "forking" messages are because of low MAX_REQUEST limit. When I attached to the process running inside the endless loop (it was before recompilation with DEBUG_FASTCGI) I got following bt #0 0xffffe424 in __kernel_vsyscall () #1 0xb712fc6d in __libc_wait (stat_loc=0xbff2d2a4) at ../sysdeps/unix/sysv/linux/wait.c:32 #2 0x0845e720 in main (argc=0, argv=Cannot access memory at address 0x4 ) at /usr/src/debug/dev-lang/php-5.2.11/php-5.2.11/sapi/cgi/cgi_main.c:1632 Previous Comments: ------------------------------------------------------------------------ [2009-11-24 20:20:27] jani@php.net 1 child is in endless loop or what? Try attach to such process with gdb and see what the backtrace says. ------------------------------------------------------------------------ [2009-11-24 03:02:09] mg at fork dot pl I rebuilt php and started up, but as I don't know what exactly causes the problem we'll have to wait until it happens... I started it like % PHP_FCGI_CHILDREN=2 PHP_FCGI_MAX_REQUESTS=100 php-cgi -e -b 127.0.0.1:30004 -c /.../php.ini Process group 2720 Forking, 0 running Forking, 1 running Wait for kids, pid 2720 Forking, 1 running Wait for kids, pid 2720 Forking, 1 running Wait for kids, pid 2720 Forking, 1 running Wait for kids, pid 2720 pstree -uap shows `-php-cgi,2720 -e -b 127.0.0.1:30004 -c /.../php.ini |-php-cgi,13821 -e -b 127.0.0.1:30004 -c /.../php.ini `-php-cgi,13822 -e -b 127.0.0.1:30004 -c /.../php.ini ------------------------------------------------------------------------ [2009-11-23 10:16:14] jani@php.net Try enable fastcgi debugging with DEBUG_FASTCGI when you compile PHP and provide the log of the failing run. ------------------------------------------------------------------------ [2009-11-23 02:24:21] mg at fork dot pl Description: ------------ fast-cgi php process loops forever during wait()ing for child process while there's no more child processes. Actual result: -------------- in cgi_main.c there's loop: 1631 while (1) { 1632 if (wait(&status) >= 0) { 1633 running--; 1634 break; 1635 } else if (exit_signal) { 1636 break; 1637 } 1638 } wait returns -1 as strace shows: wait4(-1, 0xbff2d2a4, 0, NULL) = -1 ECHILD (No child processes) and loop never breaks (as apparently exit_signal is set to 0). ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=50265&edit=1