[Asterisk-code-review] stasis: Fix crash at shutdown. (...asterisk[master])

Friendly Automation asteriskteam at digium.com
Tue Apr 30 05:44:53 CDT 2019


Friendly Automation has submitted this change and it was merged. ( https://gerrit.asterisk.org/c/asterisk/+/11306 )

Change subject: stasis: Fix crash at shutdown.
......................................................................

stasis: Fix crash at shutdown.

When compiling in dev mode, stasis statistics are enabled and can cause
a crash at shutdown due to the following:
- Containers are freed
- Topics and subscriptions remain
- When those topics and subscriptions are deallocated, they go to do
  things with the container

This changes the containers to global ao2 objects, and whenever needed
in the code, a reference must be obtained and checked before any
operations can be done.

ASTERISK-28353 #close

Change-Id: Ie7d5e907fcfcb4d65bd36d5e4eb923126fde8d33
---
M main/stasis.c
1 file changed, 111 insertions(+), 20 deletions(-)

Approvals:
  Kevin Harwell: Looks good to me, but someone else must approve
  Joshua Colp: Looks good to me, approved
  Friendly Automation: Approved for Submit



diff --git a/main/stasis.c b/main/stasis.c
index e8ce0c7..3623dab 100644
--- a/main/stasis.c
+++ b/main/stasis.c
@@ -323,11 +323,11 @@
 /*! The number of buckets to use for subscription statistics */
 #define SUBSCRIPTION_STATISTICS_BUCKETS 57
 
-/*! Container which stores statistics for topics */
-static struct ao2_container *topic_statistics;
+/*! Global container which stores statistics for topics */
+static AO2_GLOBAL_OBJ_STATIC(topic_statistics);
 
-/*! Container which stores statistics for subscriptions */
-static struct ao2_container *subscription_statistics;
+/*! Global container which stores statistics for subscriptions */
+static AO2_GLOBAL_OBJ_STATIC(subscription_statistics);
 
 /*! \internal */
 struct stasis_message_type_statistics {
@@ -429,6 +429,9 @@
 static void topic_dtor(void *obj)
 {
 	struct stasis_topic *topic = obj;
+#ifdef AST_DEVMODE
+	struct ao2_container *topic_stats;
+#endif
 
 	ast_debug(2, "Destroying topic. name: %s, detail: %s\n",
 			topic->name, topic->detail);
@@ -443,7 +446,11 @@
 
 #ifdef AST_DEVMODE
 	if (topic->statistics) {
-		ao2_unlink(topic_statistics, topic->statistics);
+		topic_stats = ao2_global_obj_ref(topic_statistics);
+		if (topic_stats) {
+			ao2_unlink(topic_stats, topic->statistics);
+			ao2_ref(topic_stats, -1);
+		}
 		ao2_ref(topic->statistics, -1);
 	}
 #endif
@@ -460,6 +467,11 @@
 static struct stasis_topic_statistics *stasis_topic_statistics_create(struct stasis_topic *topic)
 {
 	struct stasis_topic_statistics *statistics;
+	RAII_VAR(struct ao2_container *, topic_stats, ao2_global_obj_ref(topic_statistics), ao2_cleanup);
+
+	if (!topic_stats) {
+		return NULL;
+	}
 
 	statistics = ao2_alloc(sizeof(*statistics) + strlen(topic->name) + 1, topic_statistics_destroy);
 	if (!statistics) {
@@ -475,7 +487,7 @@
 	/* This is strictly used for the pointer address when showing the topic */
 	statistics->topic = topic;
 	strcpy(statistics->name, topic->name); /* SAFE */
-	ao2_link(topic_statistics, statistics);
+	ao2_link(topic_stats, statistics);
 
 	return statistics;
 }
@@ -694,6 +706,9 @@
 static void subscription_dtor(void *obj)
 {
 	struct stasis_subscription *sub = obj;
+#ifdef AST_DEVMODE
+	struct ao2_container *subscription_stats;
+#endif
 
 	/* Subscriptions need to be manually unsubscribed before destruction
 	 * b/c there's a cyclic reference between topics and subscriptions */
@@ -713,7 +728,11 @@
 
 #ifdef AST_DEVMODE
 	if (sub->statistics) {
-		ao2_unlink(subscription_statistics, sub->statistics);
+		subscription_stats = ao2_global_obj_ref(subscription_statistics);
+		if (subscription_stats) {
+			ao2_unlink(subscription_stats, sub->statistics);
+			ao2_ref(subscription_stats, -1);
+		}
 		ao2_ref(sub->statistics, -1);
 	}
 #endif
@@ -797,6 +816,11 @@
 	const char *func)
 {
 	struct stasis_subscription_statistics *statistics;
+	RAII_VAR(struct ao2_container *, subscription_stats, ao2_global_obj_ref(subscription_statistics), ao2_cleanup);
+
+	if (!subscription_stats) {
+		return NULL;
+	}
 
 	statistics = ao2_alloc(sizeof(*statistics) + strlen(sub->uniqueid) + 1, subscription_statistics_destroy);
 	if (!statistics) {
@@ -816,7 +840,7 @@
 	statistics->uses_threadpool = use_thread_pool;
 	strcpy(statistics->uniqueid, sub->uniqueid); /* SAFE */
 	statistics->sub = sub;
-	ao2_link(subscription_statistics, statistics);
+	ao2_link(subscription_stats, statistics);
 
 	return statistics;
 }
@@ -2441,6 +2465,7 @@
 static char *statistics_show_subscriptions(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	struct ao2_container *sorted_subscriptions;
+	struct ao2_container *subscription_stats;
 	struct ao2_iterator iter;
 	struct stasis_subscription_statistics *statistics;
 	int count = 0;
@@ -2465,19 +2490,29 @@
 		return CLI_SHOWUSAGE;
 	}
 
+	subscription_stats = ao2_global_obj_ref(subscription_statistics);
+	if (!subscription_stats) {
+		ast_cli(a->fd, "Could not fetch subscription_statistics container\n");
+		return CLI_FAILURE;
+	}
+
 	sorted_subscriptions = ao2_container_alloc_rbtree(AO2_ALLOC_OPT_LOCK_NOLOCK, 0,
 		stasis_subscription_statistics_sort_fn, NULL);
 	if (!sorted_subscriptions) {
+		ao2_ref(subscription_stats, -1);
 		ast_cli(a->fd, "Could not create container for sorting subscription statistics\n");
 		return CLI_SUCCESS;
 	}
 
-	if (ao2_container_dup(sorted_subscriptions, subscription_statistics, 0)) {
+	if (ao2_container_dup(sorted_subscriptions, subscription_stats, 0)) {
 		ao2_ref(sorted_subscriptions, -1);
+		ao2_ref(subscription_stats, -1);
 		ast_cli(a->fd, "Could not sort subscription statistics\n");
 		return CLI_SUCCESS;
 	}
 
+	ao2_ref(subscription_stats, -1);
+
 	ast_cli(a->fd, "\n" FMT_HEADERS, "Subscription", "Dropped", "Passed", "Lowest Invoke", "Highest Invoke");
 
 	iter = ao2_iterator_init(sorted_subscriptions, 0);
@@ -2510,12 +2545,18 @@
 static char *subscription_statistics_complete_name(const char *word, int state)
 {
 	struct stasis_subscription_statistics *statistics;
+	struct ao2_container *subscription_stats;
 	struct ao2_iterator it_statistics;
 	int wordlen = strlen(word);
 	int which = 0;
 	char *result = NULL;
 
-	it_statistics = ao2_iterator_init(subscription_statistics, 0);
+	subscription_stats = ao2_global_obj_ref(subscription_statistics);
+	if (!subscription_stats) {
+		return result;
+	}
+
+	it_statistics = ao2_iterator_init(subscription_stats, 0);
 	while ((statistics = ao2_iterator_next(&it_statistics))) {
 		if (!strncasecmp(word, statistics->uniqueid, wordlen)
 			&& ++which > state) {
@@ -2527,6 +2568,7 @@
 		}
 	}
 	ao2_iterator_destroy(&it_statistics);
+	ao2_ref(subscription_stats, -1);
 	return result;
 }
 
@@ -2537,6 +2579,7 @@
 static char *statistics_show_subscription(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	struct stasis_subscription_statistics *statistics;
+	struct ao2_container *subscription_stats;
 	struct ao2_iterator i;
 	char *name;
 
@@ -2559,12 +2602,21 @@
 		return CLI_SHOWUSAGE;
 	}
 
-	statistics = ao2_find(subscription_statistics, a->argv[4], OBJ_SEARCH_KEY);
+	subscription_stats = ao2_global_obj_ref(subscription_statistics);
+	if (!subscription_stats) {
+		ast_cli(a->fd, "Could not fetch subcription_statistics container\n");
+		return CLI_FAILURE;
+	}
+
+	statistics = ao2_find(subscription_stats, a->argv[4], OBJ_SEARCH_KEY);
 	if (!statistics) {
+		ao2_ref(subscription_stats, -1);
 		ast_cli(a->fd, "Specified subscription '%s' does not exist\n", a->argv[4]);
 		return CLI_FAILURE;
 	}
 
+	ao2_ref(subscription_stats, -1);
+
 	ast_cli(a->fd, "Subscription: %s\n", statistics->uniqueid);
 	ast_cli(a->fd, "Pointer Address: %p\n", statistics->sub);
 	ast_cli(a->fd, "Source filename: %s\n", S_OR(statistics->file, "<unavailable>"));
@@ -2607,6 +2659,7 @@
 static char *statistics_show_topics(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	struct ao2_container *sorted_topics;
+	struct ao2_container *topic_stats;
 	struct ao2_iterator iter;
 	struct stasis_topic_statistics *statistics;
 	int count = 0;
@@ -2631,19 +2684,29 @@
 		return CLI_SHOWUSAGE;
 	}
 
+	topic_stats = ao2_global_obj_ref(topic_statistics);
+	if (!topic_stats) {
+		ast_cli(a->fd, "Could not fetch topic_statistics container\n");
+		return CLI_FAILURE;
+	}
+
 	sorted_topics = ao2_container_alloc_rbtree(AO2_ALLOC_OPT_LOCK_NOLOCK, 0,
 		stasis_topic_statistics_sort_fn, NULL);
 	if (!sorted_topics) {
+		ao2_ref(topic_stats, -1);
 		ast_cli(a->fd, "Could not create container for sorting topic statistics\n");
 		return CLI_SUCCESS;
 	}
 
-	if (ao2_container_dup(sorted_topics, topic_statistics, 0)) {
+	if (ao2_container_dup(sorted_topics, topic_stats, 0)) {
 		ao2_ref(sorted_topics, -1);
+		ao2_ref(topic_stats, -1);
 		ast_cli(a->fd, "Could not sort topic statistics\n");
 		return CLI_SUCCESS;
 	}
 
+	ao2_ref(topic_stats, -1);
+
 	ast_cli(a->fd, "\n" FMT_HEADERS, "Topic", "Subscribers", "Dropped", "Dispatched", "Lowest Dispatch", "Highest Dispatch");
 
 	iter = ao2_iterator_init(sorted_topics, 0);
@@ -2677,12 +2740,18 @@
 static char *topic_statistics_complete_name(const char *word, int state)
 {
 	struct stasis_topic_statistics *statistics;
+	struct ao2_container *topic_stats;
 	struct ao2_iterator it_statistics;
 	int wordlen = strlen(word);
 	int which = 0;
 	char *result = NULL;
 
-	it_statistics = ao2_iterator_init(topic_statistics, 0);
+	topic_stats = ao2_global_obj_ref(topic_statistics);
+	if (!topic_stats) {
+		return result;
+	}
+
+	it_statistics = ao2_iterator_init(topic_stats, 0);
 	while ((statistics = ao2_iterator_next(&it_statistics))) {
 		if (!strncasecmp(word, statistics->name, wordlen)
 			&& ++which > state) {
@@ -2694,6 +2763,7 @@
 		}
 	}
 	ao2_iterator_destroy(&it_statistics);
+	ao2_ref(topic_stats, -1);
 	return result;
 }
 
@@ -2704,6 +2774,7 @@
 static char *statistics_show_topic(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	struct stasis_topic_statistics *statistics;
+	struct ao2_container *topic_stats;
 	struct ao2_iterator i;
 	char *uniqueid;
 
@@ -2726,12 +2797,21 @@
 		return CLI_SHOWUSAGE;
 	}
 
-	statistics = ao2_find(topic_statistics, a->argv[4], OBJ_SEARCH_KEY);
+	topic_stats = ao2_global_obj_ref(topic_statistics);
+	if (!topic_stats) {
+		ast_cli(a->fd, "Could not fetch topic_statistics container\n");
+		return CLI_FAILURE;
+	}
+
+	statistics = ao2_find(topic_stats, a->argv[4], OBJ_SEARCH_KEY);
 	if (!statistics) {
+		ao2_ref(topic_stats, -1);
 		ast_cli(a->fd, "Specified topic '%s' does not exist\n", a->argv[4]);
 		return CLI_FAILURE;
 	}
 
+	ao2_ref(topic_stats, -1);
+
 	ast_cli(a->fd, "Topic: %s\n", statistics->name);
 	ast_cli(a->fd, "Pointer Address: %p\n", statistics->topic);
 	ast_cli(a->fd, "Number of messages published that went to no subscriber: %d\n", statistics->messages_not_dispatched);
@@ -2939,8 +3019,8 @@
 #ifdef AST_DEVMODE
 	ast_cli_unregister_multiple(cli_stasis_statistics, ARRAY_LEN(cli_stasis_statistics));
 	AST_VECTOR_FREE(&message_type_statistics);
-	ao2_cleanup(subscription_statistics);
-	ao2_cleanup(topic_statistics);
+	ao2_global_obj_release(subscription_statistics);
+	ao2_global_obj_release(topic_statistics);
 #endif
 	ast_cli_unregister_multiple(cli_stasis, ARRAY_LEN(cli_stasis));
 	ao2_cleanup(topic_all);
@@ -2958,6 +3038,10 @@
 	struct stasis_config *cfg;
 	int cache_init;
 	struct ast_threadpool_options threadpool_opts = { 0, };
+#ifdef AST_DEVMODE
+	struct ao2_container *subscription_stats;
+	struct ao2_container *topic_stats;
+#endif
 
 	/* Be sure the types are cleaned up after the message bus */
 	ast_register_cleanup(stasis_cleanup);
@@ -3053,15 +3137,22 @@
 	/* Statistics information is stored separately so that we don't alter or interrupt the lifetime of the underlying
 	 * topic or subscripton.
 	 */
-	subscription_statistics = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, SUBSCRIPTION_STATISTICS_BUCKETS,
+	subscription_stats = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, SUBSCRIPTION_STATISTICS_BUCKETS,
 		subscription_statistics_hash, 0, subscription_statistics_cmp);
-	if (!subscription_statistics) {
+	if (!subscription_stats) {
 		return -1;
 	}
+	ao2_global_obj_replace_unref(subscription_statistics, subscription_stats);
+	ao2_cleanup(subscription_stats);
 
-	topic_statistics = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, TOPIC_STATISTICS_BUCKETS,
+	topic_stats = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, TOPIC_STATISTICS_BUCKETS,
 		topic_statistics_hash, 0, topic_statistics_cmp);
-	if (!topic_statistics) {
+	if (!topic_stats) {
+		return -1;
+	}
+	ao2_global_obj_replace_unref(topic_statistics, topic_stats);
+	ao2_cleanup(topic_stats);
+	if (!topic_stats) {
 		return -1;
 	}
 

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Gerrit-Project: asterisk
Gerrit-Branch: master
Gerrit-Change-Id: Ie7d5e907fcfcb4d65bd36d5e4eb923126fde8d33
Gerrit-Change-Number: 11306
Gerrit-PatchSet: 3
Gerrit-Owner: Benjamin Keith Ford <bford at digium.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Kevin Harwell <kharwell at digium.com>
Gerrit-MessageType: merged
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