X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-registry.c;h=6e9f0699b334bbeebb00957b0e9a9b0bd486ea1b;hb=dc3b758c34398d9eeee3f9be91a3c24e3b7f0e92;hp=6c483e4b71c3107b614cc6201a53719d88307fd9;hpb=af6142cf6f9ff4657f3c80b4c19df50247a86e91;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/ust-registry.c b/src/bin/lttng-sessiond/ust-registry.c
index 6c483e4b7..6e9f0699b 100644
--- a/src/bin/lttng-sessiond/ust-registry.c
+++ b/src/bin/lttng-sessiond/ust-registry.c
@@ -23,6 +23,7 @@
 #include <lttng/lttng.h>
 
 #include "ust-registry.h"
+#include "utils.h"
 
 /*
  * Hash table match function for event in the registry.
@@ -308,12 +309,28 @@ void ust_registry_destroy_event(struct ust_registry_channel *chan,
 	return;
 }
 
+/*
+ * We need to execute ht_destroy outside of RCU read-side critical
+ * section and outside of call_rcu thread, so we postpone its execution
+ * using ht_cleanup_push. It is simpler than to change the semantic of
+ * the many callers of delete_ust_app_session().
+ */
+static
+void destroy_channel_rcu(struct rcu_head *head)
+{
+	struct ust_registry_channel *chan =
+		caa_container_of(head, struct ust_registry_channel, rcu_head);
+
+	if (chan->ht) {
+		ht_cleanup_push(chan->ht);
+	}
+	free(chan);
+}
+
 /*
  * Destroy every element of the registry and free the memory. This does NOT
  * free the registry pointer since it might not have been allocated before so
  * it's the caller responsability.
- *
- * This MUST be called within a RCU read side lock section.
  */
 static void destroy_channel(struct ust_registry_channel *chan)
 {
@@ -322,14 +339,14 @@ static void destroy_channel(struct ust_registry_channel *chan)
 
 	assert(chan);
 
+	rcu_read_lock();
 	/* Destroy all event associated with this registry. */
 	cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
 		/* Delete the node from the ht and free it. */
 		ust_registry_destroy_event(chan, event);
 	}
-	lttng_ht_destroy(chan->ht);
-
-	free(chan);
+	rcu_read_unlock();
+	call_rcu(&chan->rcu_head, destroy_channel_rcu);
 }
 
 /*
@@ -347,7 +364,7 @@ int ust_registry_channel_add(struct ust_registry_session *session,
 	if (!chan) {
 		PERROR("zmalloc ust registry channel");
 		ret = -ENOMEM;
-		goto error;
+		goto error_alloc;
 	}
 
 	chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
@@ -376,7 +393,11 @@ int ust_registry_channel_add(struct ust_registry_session *session,
 	lttng_ht_add_unique_u64(session->channels, &chan->node);
 	rcu_read_unlock();
 
+	return 0;
+
 error:
+	destroy_channel(chan);
+error_alloc:
 	return ret;
 }
 
@@ -418,22 +439,24 @@ void ust_registry_channel_del_free(struct ust_registry_session *session,
 {
 	struct lttng_ht_iter iter;
 	struct ust_registry_channel *chan;
+	int ret;
 
 	assert(session);
 
 	rcu_read_lock();
 	chan = ust_registry_channel_find(session, key);
 	if (!chan) {
+		rcu_read_unlock();
 		goto end;
 	}
 
 	iter.iter.node = &chan->node.node;
-	lttng_ht_del(session->channels, &iter);
-
+	ret = lttng_ht_del(session->channels, &iter);
+	assert(!ret);
+	rcu_read_unlock();
 	destroy_channel(chan);
 
 end:
-	rcu_read_unlock();
 	return;
 }
 
@@ -464,7 +487,7 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
 	session = zmalloc(sizeof(*session));
 	if (!session) {
 		PERROR("zmalloc ust registry session");
-		goto error;
+		goto error_alloc;
 	}
 
 	pthread_mutex_init(&session->lock, NULL);
@@ -500,6 +523,8 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
 	return 0;
 
 error:
+	ust_registry_session_destroy(session);
+error_alloc:
 	return -1;
 }
 
@@ -525,8 +550,10 @@ void ust_registry_session_destroy(struct ust_registry_session *reg)
 		assert(!ret);
 		destroy_channel(chan);
 	}
-	lttng_ht_destroy(reg->channels);
 	rcu_read_unlock();
 
+	if (reg->channels) {
+		ht_cleanup_push(reg->channels);
+	}
 	free(reg->metadata);
 }