Mercurial > hg > nginx
view src/event/ngx_event_posted.h @ 7969:84c60a3cd12a stable-1.20
Changed ngx_chain_update_chains() to test tag first (ticket #2248).
Without this change, aio used with HTTP/2 can result in connection hang,
as observed with "aio threads; aio_write on;" and proxying (ticket #2248).
The problem is that HTTP/2 updates buffers outside of the output filters
(notably, marks them as sent), and then posts a write event to call
output filters. If a filter does not call the next one for some reason
(for example, because of an AIO operation in progress), this might
result in a state when the owner of a buffer already called
ngx_chain_update_chains() and can reuse the buffer, while the same buffer
is still sitting in the busy chain of some other filter.
In the particular case a buffer was sitting in output chain's ctx->busy,
and was reused by event pipe. Output chain's ctx->busy was permanently
blocked by it, and this resulted in connection hang.
Fix is to change ngx_chain_update_chains() to skip buffers from other
modules unconditionally, without trying to wait for these buffers to
become empty.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sat, 30 Oct 2021 02:39:19 +0300 |
parents | f1720934c45b |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_EVENT_POSTED_H_INCLUDED_ #define _NGX_EVENT_POSTED_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define ngx_post_event(ev, q) \ \ if (!(ev)->posted) { \ (ev)->posted = 1; \ ngx_queue_insert_tail(q, &(ev)->queue); \ \ ngx_log_debug1(NGX_LOG_DEBUG_CORE, (ev)->log, 0, "post event %p", ev);\ \ } else { \ ngx_log_debug1(NGX_LOG_DEBUG_CORE, (ev)->log, 0, \ "update posted event %p", ev); \ } #define ngx_delete_posted_event(ev) \ \ (ev)->posted = 0; \ ngx_queue_remove(&(ev)->queue); \ \ ngx_log_debug1(NGX_LOG_DEBUG_CORE, (ev)->log, 0, \ "delete posted event %p", ev); void ngx_event_process_posted(ngx_cycle_t *cycle, ngx_queue_t *posted); void ngx_event_move_posted_next(ngx_cycle_t *cycle); extern ngx_queue_t ngx_posted_accept_events; extern ngx_queue_t ngx_posted_next_events; extern ngx_queue_t ngx_posted_events; #endif /* _NGX_EVENT_POSTED_H_INCLUDED_ */