From 9b67ca0e410a17fbdef14de5e358782f0195ab96 Mon Sep 17 00:00:00 2001 From: Igor Sysoev Date: Wed, 4 Nov 2009 19:41:08 +0000 Subject: Fix a bug introduced in r2032: After a child process has read a terminate message from a channel, the process tries to read the channel again. The kernel (at least FreeBSD) may preempt the process and sends a SIGIO signal to a master process. The master process sends a new terminate message, the kernel switches again to the the child process, and the child process reads the messages instead of an EAGAIN error. And this may repeat over and over. Being that the child process can not exit the cycle and test the termination flag set by the message handler. The fix disallow the master process to send a new terminate message on SIGIO signal reception. It may send the message only on SIGALARM signal. --- src/os/unix/ngx_process_cycle.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'src/os/unix/ngx_process_cycle.c') diff --git a/src/os/unix/ngx_process_cycle.c b/src/os/unix/ngx_process_cycle.c index 15a2a8bab..4b7403054 100644 --- a/src/os/unix/ngx_process_cycle.c +++ b/src/os/unix/ngx_process_cycle.c @@ -86,7 +86,7 @@ ngx_master_process_cycle(ngx_cycle_t *cycle) u_char *p; size_t size; ngx_int_t i; - ngx_uint_t n; + ngx_uint_t n, sigio; sigset_t set; struct itimerval itv; ngx_uint_t live; @@ -139,11 +139,13 @@ ngx_master_process_cycle(ngx_cycle_t *cycle) ngx_new_binary = 0; delay = 0; + sigio = 0; live = 1; for ( ;; ) { if (delay) { if (ngx_sigalrm) { + sigio = 0; delay *= 2; ngx_sigalrm = 0; } @@ -168,7 +170,8 @@ ngx_master_process_cycle(ngx_cycle_t *cycle) ngx_time_update(0, 0); - ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "wake up"); + ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, + "wake up, sigio %i", sigio); if (ngx_reap) { ngx_reap = 0; @@ -186,6 +189,13 @@ ngx_master_process_cycle(ngx_cycle_t *cycle) delay = 50; } + if (sigio) { + sigio--; + continue; + } + + sigio = ccf->worker_processes + 2 /* cache processes */; + if (delay > 1000) { ngx_signal_worker_processes(cycle, SIGKILL); } else { -- cgit v1.2.3