Mercurial > hg > nginx
comparison src/http/v2/ngx_http_v2.h @ 6891:749bcfdf097a stable-1.10
HTTP/2: fixed posted streams handling.
A bug was introduced by 82efcedb310b that could lead to timing out of
responses or segmentation fault, when accept_mutex was enabled.
The output queue in HTTP/2 can contain frames from different streams.
When the queue is sent, all related write handlers need to be called.
In order to do so, the streams were added to the h2c->posted queue
after handling sent frames. Then this queue was processed in
ngx_http_v2_write_handler().
If accept_mutex is enabled, the event's "ready" flag is set but its
handler is not called immediately. Instead, the event is added to
the ngx_posted_events queue. At the same time in this queue can be
events from upstream connections. Such events can result in sending
output queue before ngx_http_v2_write_handler() is triggered. And
at the time ngx_http_v2_write_handler() is called, the output queue
can be already empty with some streams added to h2c->posted.
But after 82efcedb310b, these streams weren't processed if all frames
have already been sent and the output queue was empty. This might lead
to a situation when a number of streams were get stuck in h2c->posted
queue for a long time. Eventually these streams might get closed by
the send timeout.
In the worst case this might also lead to a segmentation fault, if
already freed stream was left in the h2c->posted queue. This could
happen if one of the streams was terminated but wasn't closed, due to
the HEADERS frame or a partially sent DATA frame left in the output
queue. If this happened the ngx_http_v2_filter_cleanup() handler
removed the stream from the h2c->waiting or h2c->posted queue on
termination stage, before the frame has been sent, and the stream
was again added to the h2c->posted queue after the frame was sent.
In order to fix all these problems and simplify the code, write
events of fake stream connections are now added to ngx_posted_events
instead of using a custom h2c->posted queue.
author | Valentin Bartenev <vbart@nginx.com> |
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date | Mon, 28 Nov 2016 20:58:14 +0300 |
parents | 09cf90250844 |
children |
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6890:16487f9e6665 | 6891:749bcfdf097a |
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135 | 135 |
136 ngx_http_v2_node_t **streams_index; | 136 ngx_http_v2_node_t **streams_index; |
137 | 137 |
138 ngx_http_v2_out_frame_t *last_out; | 138 ngx_http_v2_out_frame_t *last_out; |
139 | 139 |
140 ngx_queue_t posted; | |
141 ngx_queue_t dependencies; | 140 ngx_queue_t dependencies; |
142 ngx_queue_t closed; | 141 ngx_queue_t closed; |
143 | 142 |
144 ngx_uint_t last_sid; | 143 ngx_uint_t last_sid; |
145 | 144 |
190 | 189 |
191 size_t header_limit; | 190 size_t header_limit; |
192 | 191 |
193 ngx_pool_t *pool; | 192 ngx_pool_t *pool; |
194 | 193 |
195 unsigned handled:1; | 194 unsigned waiting:1; |
196 unsigned blocked:1; | 195 unsigned blocked:1; |
197 unsigned exhausted:1; | 196 unsigned exhausted:1; |
198 unsigned in_closed:1; | 197 unsigned in_closed:1; |
199 unsigned out_closed:1; | 198 unsigned out_closed:1; |
200 unsigned rst_sent:1; | 199 unsigned rst_sent:1; |