Mercurial > hg > nginx
view src/event/ngx_event_posted.c @ 3755:76e3a93821b1
fix race condition if during reconfiguration two cache managers try
to delete old inactive entries: one of them removes a entry just locked by
other manager from the queue and the rbtree as long inactive entry,
causes the latter manager to segfault leaving cache mutex locked,
the bug has been introduced in r3727
author | Igor Sysoev <igor@sysoev.ru> |
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date | Thu, 02 Sep 2010 14:31:47 +0000 |
parents | 9c2f3ed7a247 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ngx_thread_volatile ngx_event_t *ngx_posted_accept_events; ngx_thread_volatile ngx_event_t *ngx_posted_events; #if (NGX_THREADS) ngx_mutex_t *ngx_posted_events_mutex; #endif void ngx_event_process_posted(ngx_cycle_t *cycle, ngx_thread_volatile ngx_event_t **posted) { ngx_event_t *ev; for ( ;; ) { ev = (ngx_event_t *) *posted; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "posted event %p", ev); if (ev == NULL) { return; } ngx_delete_posted_event(ev); ev->handler(ev); } } #if (NGX_THREADS) && !(NGX_WIN32) void ngx_wakeup_worker_thread(ngx_cycle_t *cycle) { ngx_int_t i; #if 0 ngx_uint_t busy; ngx_event_t *ev; busy = 1; if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) { return; } for (ev = (ngx_event_t *) ngx_posted_events; ev; ev = ev->next) { if (*(ev->lock) == 0) { busy = 0; break; } } ngx_mutex_unlock(ngx_posted_events_mutex); if (busy) { return; } #endif for (i = 0; i < ngx_threads_n; i++) { if (ngx_threads[i].state == NGX_THREAD_FREE) { ngx_cond_signal(ngx_threads[i].cv); return; } } } ngx_int_t ngx_event_thread_process_posted(ngx_cycle_t *cycle) { ngx_event_t *ev; for ( ;; ) { ev = (ngx_event_t *) ngx_posted_events; for ( ;; ) { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "posted event %p", ev); if (ev == NULL) { return NGX_OK; } if (ngx_trylock(ev->lock) == 0) { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "posted event %p is busy", ev); ev = ev->next; continue; } if (ev->lock != ev->own_lock) { if (*(ev->own_lock)) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "the own lock of the posted event %p is busy", ev); ngx_unlock(ev->lock); ev = ev->next; continue; } *(ev->own_lock) = 1; } ngx_delete_posted_event(ev); ev->locked = 1; ev->ready |= ev->posted_ready; ev->timedout |= ev->posted_timedout; ev->pending_eof |= ev->posted_eof; #if (NGX_HAVE_KQUEUE) ev->kq_errno |= ev->posted_errno; #endif if (ev->posted_available) { ev->available = ev->posted_available; } ev->posted_ready = 0; ev->posted_timedout = 0; ev->posted_eof = 0; #if (NGX_HAVE_KQUEUE) ev->posted_errno = 0; #endif ev->posted_available = 0; ngx_mutex_unlock(ngx_posted_events_mutex); ev->handler(ev); ngx_mutex_lock(ngx_posted_events_mutex); if (ev->locked) { ngx_unlock(ev->lock); if (ev->lock != ev->own_lock) { ngx_unlock(ev->own_lock); } } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "posted event %p is done", ev); break; } } } #else void ngx_wakeup_worker_thread(ngx_cycle_t *cycle) { } #endif