ChangeLogTag:Fri Feb 14 16:34:46 UTC 2014 Steve Huston <shuston@riverace.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/ACE/ChangeLog b/ACE/ChangeLog
index ee9628c898d..dd9586090de 100644
--- a/ACE/ChangeLog
+++ b/ACE/ChangeLog
@@ -1,3 +1,12 @@
+Fri Feb 14 16:34:46 UTC 2014  Steve Huston  <shuston@riverace.com>
+
+        * ace/Dev_Poll_Reactor.cpp (dispatch_io_event): Do not dispatch to
+          a handler that is suspended. Prevents multiple callbacks to the
+          same handler at the same time when multiple threads are dispatching
+          and changing registrations at the same time. Fixes Bugzilla 4129.
+          Thank you to Alexey Zubko and Howard Finer for both coming up with
+          the same answer independently!
+
 Wed Feb  5 19:07:37 UTC 2014  Steve Huston  <shuston@riverace.com>
 
         * rpmbuild/ace-tao.spec: Added support for --without tao (and
diff --git a/ACE/ace/Dev_Poll_Reactor.cpp b/ACE/ace/Dev_Poll_Reactor.cpp
index ec0817a070b..81bc9091626 100644
--- a/ACE/ace/Dev_Poll_Reactor.cpp
+++ b/ACE/ace/Dev_Poll_Reactor.cpp
@@ -1176,6 +1176,12 @@ ACE_Dev_Poll_Reactor::dispatch_io_event (Token_Guard &guard)
         info = this->handler_rep_.find (handle);
         if (info == 0)   // No registered handler any longer
           return 0;
+	// It is possible another thread has changed (and possibly re-armed)
+	// this handle mask before current thread obtained the repo lock.
+	// If that did happen and this handler is still suspended, don't
+	// dispatch on top of another callback. See Bugzilla 4129.
+	if (info->suspended)
+	  return 0;
 
         // Figure out what to do first in order to make it easier to manage
         // the bit twiddling and possible pfds increment before releasing