FS-11379: [freeswitch-core] Rare race condition in state machine #resolve

src/include/switch_types.h

@@ -1570,6 +1570,7 @@ typedef enum {
 	CF_PROCESSING_STREAM_CHANGE,
 	CF_STREAM_CHANGED,
 	CF_ARRANGED_BRIDGE,
+	CF_STATE_REPEAT,
 	/* WARNING: DO NOT ADD ANY FLAGS BELOW THIS LINE */
 	/* IF YOU ADD NEW ONES CHECK IF THEY SHOULD PERSIST OR ZERO THEM IN switch_core_session.c switch_core_session_request_xml() */
 	CF_FLAG_MAX

src/switch_core_session.c

@@ -1439,6 +1439,7 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_wake_session_thread(switch_c
 	} else {
 		if (switch_channel_state_thread_trylock(session->channel) == SWITCH_STATUS_SUCCESS) {
 			/* We've beat them for sure, as soon as we release this lock, they will be checking their queue on the next line. */
+			switch_channel_set_flag(session->channel, CF_STATE_REPEAT);
 			switch_channel_state_thread_unlock(session->channel);
 		} else {
 			/* What luck!  The channel has already started going to sleep *after* we checked if we need to wake it up.

src/switch_core_state_machine.c

@@ -690,29 +690,26 @@ SWITCH_DECLARE(void) switch_core_session_run(switch_core_session_t *session)
 					switch_channel_hangup(session->channel, SWITCH_CAUSE_WRONG_CALL_STATE);
 				}
 			} else {
-				switch_ivr_parse_all_events(session);
+				switch_channel_state_thread_lock(session->channel);
+
 				switch_ivr_parse_all_events(session);
 
-				if (switch_channel_get_state(session->channel) == switch_channel_get_running_state(session->channel)) {
-					switch_channel_state_thread_lock(session->channel);
+				if (switch_channel_test_flag(session->channel, CF_STATE_REPEAT)) {
+					switch_channel_clear_flag(session->channel, CF_STATE_REPEAT);
+				} else if (switch_channel_get_state(session->channel) == switch_channel_get_running_state(session->channel)) {
 					switch_channel_set_flag(session->channel, CF_THREAD_SLEEPING);
-					if (switch_channel_get_state(session->channel) == switch_channel_get_running_state(session->channel)) {
-						switch_ivr_parse_all_events(session);
-						switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG1, "%s session thread sleep state: %s!\n",
-										  switch_channel_get_name(session->channel),
-										  switch_channel_state_name(switch_channel_get_running_state(session->channel)));
-						switch_thread_cond_wait(session->cond, session->mutex);
-						switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG1, "%s session thread wake state: %s!\n",
-										  switch_channel_get_name(session->channel),
-										  switch_channel_state_name(switch_channel_get_running_state(session->channel)));
-
-
-					}
+					switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG1, "%s session thread sleep state: %s!\n",
+									  switch_channel_get_name(session->channel),
+									  switch_channel_state_name(switch_channel_get_running_state(session->channel)));
+					switch_thread_cond_wait(session->cond, session->mutex);
+					switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG1, "%s session thread wake state: %s!\n",
+									  switch_channel_get_name(session->channel),
+									  switch_channel_state_name(switch_channel_get_running_state(session->channel)));					
 					switch_channel_clear_flag(session->channel, CF_THREAD_SLEEPING);
-					switch_channel_state_thread_unlock(session->channel);
 				}
 
-				switch_ivr_parse_all_events(session);
+				switch_channel_state_thread_unlock(session->channel);
+
 				switch_ivr_parse_all_events(session);
 			}
 		}