Merged revisions 67020 via svnmerge from
authorRussell Bryant <russell@russellbryant.com>
Mon, 4 Jun 2007 15:50:46 +0000 (15:50 +0000)
committerRussell Bryant <russell@russellbryant.com>
Mon, 4 Jun 2007 15:50:46 +0000 (15:50 +0000)
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r67020 | russell | 2007-06-04 10:47:40 -0500 (Mon, 04 Jun 2007) | 7 lines

Resolve a deadlock in chan_iax2.  When handling an implicit ACK to a frame that
was marked as the final transmission for a call, don't call iax2_destroy() for
that call while the global frame queue is still locked.  There is a very nice
explanation of the deadlock in the report.
(issue #9663, thorough report and patch from stevedavies, additional positive
 test reports from mihai and joff_oconnell)

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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@67022 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

index b823c8d..63eddf7 100644 (file)
@@ -6844,6 +6844,7 @@ static int socket_process(struct iax2_thread *thread)
                    ((f.subclass != IAX_COMMAND_INVAL) ||
                     (f.frametype != AST_FRAME_IAX))) {
                        unsigned char x;
+                       int call_to_destroy;
                        /* XXX This code is not very efficient.  Surely there is a better way which still
                               properly handles boundary conditions? XXX */
                        /* First we have to qualify that the ACKed value is within our window */
@@ -6857,20 +6858,23 @@ static int socket_process(struct iax2_thread *thread)
                                        /* Ack the packet with the given timestamp */
                                        if (option_debug && iaxdebug)
                                                ast_log(LOG_DEBUG, "Cancelling transmission of packet %d\n", x);
+                                       call_to_destroy = 0;
                                        AST_LIST_LOCK(&queue);
                                        AST_LIST_TRAVERSE(&queue, cur, list) {
                                                /* If it's our call, and our timestamp, mark -1 retries */
                                                if ((fr->callno == cur->callno) && (x == cur->oseqno)) {
                                                        cur->retries = -1;
                                                        /* Destroy call if this is the end */
-                                                       if (cur->final) { 
-                                                               if (iaxdebug && option_debug)
-                                                                       ast_log(LOG_DEBUG, "Really destroying %d, having been acked on final message\n", fr->callno);
-                                                               iax2_destroy(fr->callno);
-                                                       }
+                                                       if (cur->final)
+                                                               call_to_destroy = fr->callno;
                                                }
                                        }
                                        AST_LIST_UNLOCK(&queue);
+                                       if (call_to_destroy) {
+                                               if (iaxdebug && option_debug)
+                                                       ast_log(LOG_DEBUG, "Really destroying %d, having been acked on final message\n", call_to_destroy);
+                                               iax2_destroy(call_to_destroy);
+                                       }
                                }
                                /* Note how much we've received acknowledgement for */
                                if (iaxs[fr->callno])