Mercurial > hg > nginx
view src/event/ngx_event_pipe.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 | adc2414856b1 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_EVENT_PIPE_H_INCLUDED_ #define _NGX_EVENT_PIPE_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> typedef struct ngx_event_pipe_s ngx_event_pipe_t; typedef ngx_int_t (*ngx_event_pipe_input_filter_pt)(ngx_event_pipe_t *p, ngx_buf_t *buf); typedef ngx_int_t (*ngx_event_pipe_output_filter_pt)(void *data, ngx_chain_t *chain); struct ngx_event_pipe_s { ngx_connection_t *upstream; ngx_connection_t *downstream; ngx_chain_t *free_raw_bufs; ngx_chain_t *in; ngx_chain_t **last_in; ngx_chain_t *writing; ngx_chain_t *out; ngx_chain_t *free; ngx_chain_t *busy; /* * the input filter i.e. that moves HTTP/1.1 chunks * from the raw bufs to an incoming chain */ ngx_event_pipe_input_filter_pt input_filter; void *input_ctx; ngx_event_pipe_output_filter_pt output_filter; void *output_ctx; #if (NGX_THREADS || NGX_COMPAT) ngx_int_t (*thread_handler)(ngx_thread_task_t *task, ngx_file_t *file); void *thread_ctx; ngx_thread_task_t *thread_task; #endif unsigned read:1; unsigned cacheable:1; unsigned single_buf:1; unsigned free_bufs:1; unsigned upstream_done:1; unsigned upstream_error:1; unsigned upstream_eof:1; unsigned upstream_blocked:1; unsigned downstream_done:1; unsigned downstream_error:1; unsigned cyclic_temp_file:1; unsigned aio:1; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ssize_t busy_size; off_t read_length; off_t length; off_t max_temp_file_size; ssize_t temp_file_write_size; ngx_msec_t read_timeout; ngx_msec_t send_timeout; ssize_t send_lowat; ngx_pool_t *pool; ngx_log_t *log; ngx_chain_t *preread_bufs; size_t preread_size; ngx_buf_t *buf_to_file; size_t limit_rate; time_t start_sec; ngx_temp_file_t *temp_file; /* STUB */ int num; }; ngx_int_t ngx_event_pipe(ngx_event_pipe_t *p, ngx_int_t do_write); ngx_int_t ngx_event_pipe_copy_input_filter(ngx_event_pipe_t *p, ngx_buf_t *buf); ngx_int_t ngx_event_pipe_add_free_buf(ngx_event_pipe_t *p, ngx_buf_t *b); #endif /* _NGX_EVENT_PIPE_H_INCLUDED_ */