Index: main/pbx.c
===================================================================
--- main/pbx.c	(revision 45159)
+++ main/pbx.c	(working copy)
@@ -2251,7 +2251,32 @@
 	}
 	if (c->cdr && ast_tvzero(c->cdr->start))
 		ast_cdr_start(c->cdr);
+
+	/* Keep a copy of the real asked extension and priority */
+	char *real_exten = ast_strdupa(c->exten);
+	int real_pri = c->priority;
+	/* Execute the 'b' extension at priority 1 */
+	set_ext_pri(c, "b", 1);
+	while (ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
+		if ((res = ast_spawn_extension(c, c->context, c->exten, c->priority, c->cid.cid_num))) {
+			/* Something bad happened, or a hangup has been requested. */
+			if (option_debug)
+				ast_log(LOG_DEBUG, "Spawn extension (%s, %s, %d) exited non-zero (res = %d) on '%s'\n", c->context, c->exten, c->priority, res, c->name);
+			if (option_verbose > 1)
+				ast_verbose(VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited non-zero (res = %d) on '%s'\n", c->context, c->exten, c->priority, res, c->name);
+			error = 1;
+			break;
+		}
+		c->priority++;
+	}
+	/* Put back the real information in the channel */
+	set_ext_pri(c, real_exten, real_pri);
+
 	for (;;) {
+		/* Check if error flag was set before going further */
+		if (error)
+			break;
+
 		char dst_exten[256];	/* buffer to accumulate digits */
 		int pos = 0;		/* XXX should check bounds */
 		int digit = 0;