Patch php-76601_kill-not-rescheduled_7.2.11_2018-09-28.patch for FPM related Bug #76601

Patch version 2018-10-16 04:34 UTC

• 2018-10-16 04:34 UTC [diff to current]

Developer: mnikulin@plesk.com

Fix php-fpm failure after concurrent reload attempts. Bug #76601

Avoid discarding of the timer that should send SIGKILL to children after
SIGTERM is sent. Prevent the following case:
* Reload (reexec) is in progress.
* New master is forking to start enough children for pools where pm is not on-demand.
* Another SIGUSR2 is received by master process.
* Master process switches to reloading state.
* Some child has not set its own signal handlers.
* SIGQUIT and SIGTERM sent by master process a caught by signal handler
  set by master process and so they are ignored (see another patch).
* A child is running, it has no reason to finish
* Master process is waiting for completion of all its children.
* SIGKILL is not scheduled after SIGTERM due to a bug around of reusing
  the same event and handler in the event loop.
* Reload has stuck.
* No incoming requests are processed besides ones handled by a few of survived children.
* Event loop is running however, systemd is receiving alive notification.
* New reload attempts do not change the state of master process.
* Most of web sites are unavailable.

Use persistent timer since rescheduling is not possible
in the current implementation of the event loop. It should
be no harm to repeatedly send SIGKILL while some children
are alive.

Index: php-7.2.11/sapi/fpm/fpm/fpm_process_ctl.c
===================================================================
--- php-7.2.11.orig/sapi/fpm/fpm/fpm_process_ctl.c
+++ php-7.2.11/sapi/fpm/fpm/fpm_process_ctl.c
@@ -59,7 +59,7 @@ static void fpm_pctl_action(struct fpm_e
 
 static int fpm_pctl_timeout_set(int sec) /* {{{ */
 {
-	fpm_event_set_timer(&pctl_event, 0, &fpm_pctl_action, NULL);
+	fpm_event_set_timer(&pctl_event, FPM_EV_PERSIST, &fpm_pctl_action, NULL);
 	fpm_event_add(&pctl_event, sec * 1000);
 	return 0;
 }