Author: mdounin
Date: 2011-11-22 17:02:21 +0000 (Tue, 22 Nov 2011)
New Revision: 4306

Log:
Protection from stale write events in epoll.

Stale write event may happen if epoll_wait() reported both read and write
events, and processing of the read event closed descriptor.

Patch by Yichun Zhang (agentzh).


Modified:
trunk/src/event/modules/ngx_epoll_module.c

Modified: trunk/src/event/modules/ngx_epoll_module.c
===================================================================
--- trunk/src/event/modules/ngx_epoll_module.c 2011-11-22 16:27:45 UTC (rev 4305)
+++ trunk/src/event/modules/ngx_epoll_module.c 2011-11-22 17:02:21 UTC (rev 4306)
@@ -681,6 +681,18 @@

wev = c->write;

+ if (c->fd == -1 || wev->instance != instance) {
+
+ /*
+ * the stale event from a file descriptor
+ * that was just closed in this iteration
+ */
+
+ ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
+ "epoll: stale event %p", c);
+ continue;
+ }
+
if ((revents & EPOLLOUT) && wev->active) {

if (flags & NGX_POST_THREAD_EVENTS) {

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