[Asterisk-code-review] chan sip: Reorder unload module to deal with stuck TCP threads. (asterisk[13])

[Corey Farrell]

Corey Farrell has uploaded a new change for review. ( https://gerrit.asterisk.org/4640 )

Change subject: chan_sip: Reorder unload_module to deal with stuck TCP threads.
......................................................................

chan_sip: Reorder unload_module to deal with stuck TCP threads.

In some situations TCP threads may become frozen.  This creates the
possibility that Asterisk could segfault if they become unfrozen after
chan_sip has been dlclose'd.  This reorders the unload_module process to
allow abort if threads do not exit within 5 seconds.

High level order as follows:
1) Unregister from the core to stop new requests.
2) Signal threads to stop
3) Clear config based tables (but do not free the table itself).
4) Verify that threads have shutdown, cancel unload if not.
5) Free all remaining memory.

ASTERISK-26586

Change-Id: Ie23692041d838fbd35ece61868f4c640960ff882
---
M channels/chan_sip.c
1 file changed, 36 insertions(+), 34 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/40/4640/1

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index f8ae5e5..21eafc7 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -1774,7 +1774,7 @@
 {
 	int i;
 	for (i = 0; i < ARRAY_LEN(event_state_compositors); i++) {
-		ao2_cleanup(event_state_compositors[i].compositor);
+		ao2_replace(event_state_compositors[i].compositor, NULL);
 	}
 }
 
@@ -35273,6 +35273,8 @@
 	struct ao2_iterator i;
 	struct timeval start;
 
+	ast_sched_dump(sched);
+
 	ast_sip_api_provider_unregister();
 
 	if (sip_cfg.websocket_enabled) {
@@ -35282,12 +35284,11 @@
 	network_change_stasis_unsubscribe();
 	acl_change_event_stasis_unsubscribe();
 
-	ast_sched_dump(sched);
-
 	/* First, take us out of the channel type list */
 	ast_channel_unregister(&sip_tech);
-
 	ast_msg_tech_unregister(&sip_msg_tech);
+	ast_cc_monitor_unregister(&sip_cc_monitor_callbacks);
+	ast_cc_agent_unregister(&sip_cc_agent_callbacks);
 
 	/* Unregister dial plan functions */
 	ast_custom_function_unregister(&sippeer_function);
@@ -35351,8 +35352,6 @@
 	}
 	ao2_iterator_destroy(&i);
 
-	unlink_all_peers_from_tables();
-
 	ast_mutex_lock(&monlock);
 	if (monitor_thread && (monitor_thread != AST_PTHREADT_STOP) && (monitor_thread != AST_PTHREADT_NULL)) {
 		pthread_t th = monitor_thread;
@@ -35366,7 +35365,19 @@
 		ast_mutex_unlock(&monlock);
 	}
 
+	if (sipsock_read_id) {
+		ast_io_remove(io, sipsock_read_id);
+		sipsock_read_id = NULL;
+	}
+	close(sipsock);
+	io_context_destroy(io);
+
+	/* Clear containers */
+	unlink_all_peers_from_tables();
 	cleanup_all_regs();
+	sip_epa_unregister_all();
+	destroy_escs();
+	clear_sip_domains();
 
 	{
 		struct ao2_iterator iter;
@@ -35395,25 +35406,6 @@
 	 */
 	ast_sched_runq(sched);
 
-	/* Free memory for local network address mask */
-	ast_free_ha(localaddr);
-
-	ast_mutex_lock(&authl_lock);
-	if (authl) {
-		ao2_t_cleanup(authl, "Removing global authentication");
-		authl = NULL;
-	}
-	ast_mutex_unlock(&authl_lock);
-
-	sip_epa_unregister_all();
-	destroy_escs();
-
-	ast_free(default_tls_cfg.certfile);
-	ast_free(default_tls_cfg.pvtfile);
-	ast_free(default_tls_cfg.cipher);
-	ast_free(default_tls_cfg.cafile);
-	ast_free(default_tls_cfg.capath);
-
 	/*
 	 * Wait awhile for the TCP/TLS thread container to become empty.
 	 *
@@ -35427,7 +35419,25 @@
 	}
 	if (ao2_container_count(threadt)) {
 		ast_debug(2, "TCP/TLS thread container did not become empty :(\n");
+
+		return -1;
 	}
+
+	/* Free memory for local network address mask */
+	ast_free_ha(localaddr);
+
+	ast_mutex_lock(&authl_lock);
+	if (authl) {
+		ao2_t_cleanup(authl, "Removing global authentication");
+		authl = NULL;
+	}
+	ast_mutex_unlock(&authl_lock);
+
+	ast_free(default_tls_cfg.certfile);
+	ast_free(default_tls_cfg.pvtfile);
+	ast_free(default_tls_cfg.cipher);
+	ast_free(default_tls_cfg.cafile);
+	ast_free(default_tls_cfg.capath);
 
 	ao2_cleanup(registry_list);
 	ao2_cleanup(subscription_mwi_list);
@@ -35442,21 +35452,13 @@
 	ao2_t_cleanup(threadt, "unref the thread table");
 	ao2_t_cleanup(sip_monitor_instances, "unref the sip_monitor_instances table");
 
-	clear_sip_domains();
 	sip_cfg.contact_acl = ast_free_acl_list(sip_cfg.contact_acl);
-	if (sipsock_read_id) {
-		ast_io_remove(io, sipsock_read_id);
-		sipsock_read_id = NULL;
-	}
-	close(sipsock);
-	io_context_destroy(io);
+
 	ast_sched_context_destroy(sched);
 	sched = NULL;
 	ast_context_destroy_by_name(used_context, "SIP");
 	ast_unload_realtime("sipregs");
 	ast_unload_realtime("sippeers");
-	ast_cc_monitor_unregister(&sip_cc_monitor_callbacks);
-	ast_cc_agent_unregister(&sip_cc_agent_callbacks);
 
 	sip_reqresp_parser_exit();
 	sip_unregister_tests();

-- 
To view, visit https://gerrit.asterisk.org/4640
To unsubscribe, visit https://gerrit.asterisk.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: Ie23692041d838fbd35ece61868f4c640960ff882
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Corey Farrell <git at cfware.com>