view src/event/ngx_event_posted.c @ 8106:8852f39311de

Fixed segfault when switching off master process during upgrade. Binary upgrades are not supported without master process, but it is, however, possible, that nginx running with master process is asked to upgrade binary, and the configuration file as available on disk at this time includes "master_process off;". If this happens, listening sockets inherited from the previous binary will have ls[i].previous set. But the old cycle on initial process startup, including startup after binary upgrade, is destroyed by ngx_init_cycle() once configuration parsing is complete. As a result, an attempt to dereference ls[i].previous in ngx_event_process_init() accesses already freed memory. Fix is to avoid looking into ls[i].previous if the old cycle is already freed. With this change it is also no longer needed to clear ls[i].previous in worker processes, so the relevant code was removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Nov 2022 23:48:53 +0300
parents f1720934c45b
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


ngx_queue_t  ngx_posted_accept_events;
ngx_queue_t  ngx_posted_next_events;
ngx_queue_t  ngx_posted_events;


void
ngx_event_process_posted(ngx_cycle_t *cycle, ngx_queue_t *posted)
{
    ngx_queue_t  *q;
    ngx_event_t  *ev;

    while (!ngx_queue_empty(posted)) {

        q = ngx_queue_head(posted);
        ev = ngx_queue_data(q, ngx_event_t, queue);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                      "posted event %p", ev);

        ngx_delete_posted_event(ev);

        ev->handler(ev);
    }
}


void
ngx_event_move_posted_next(ngx_cycle_t *cycle)
{
    ngx_queue_t  *q;
    ngx_event_t  *ev;

    for (q = ngx_queue_head(&ngx_posted_next_events);
         q != ngx_queue_sentinel(&ngx_posted_next_events);
         q = ngx_queue_next(q))
    {
        ev = ngx_queue_data(q, ngx_event_t, queue);

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                      "posted next event %p", ev);

        ev->ready = 1;
        ev->available = -1;
    }

    ngx_queue_add(&ngx_posted_events, &ngx_posted_next_events);
    ngx_queue_init(&ngx_posted_next_events);
}