X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=lttng-sessiond%2Fevent.c;h=1068707438082e2758e80105599c050967d3e581;hp=8582d2f8fc4907e59745feb07c93473ee08c7733;hb=fc34caaa25f9780eb8509f243f910c3f2aaa5a69;hpb=008dd0fe872d71d154867d25579b58a0a204d93d

diff --git a/lttng-sessiond/event.c b/lttng-sessiond/event.c
index 8582d2f8f..106870743 100644
--- a/lttng-sessiond/event.c
+++ b/lttng-sessiond/event.c
@@ -359,7 +359,7 @@ error:
 int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 		struct ltt_ust_channel *uchan, struct lttng_event *event)
 {
-	int ret, to_create = 0;
+	int ret = LTTCOMM_OK, to_create = 0;
 	struct ltt_ust_event *uevent;
 
 	uevent = trace_ust_find_event_by_name(uchan->events, event->name);
@@ -369,6 +369,7 @@ int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 			ret = LTTCOMM_FATAL;
 			goto error;
 		}
+		/* Valid to set it after the goto error since uevent is still NULL */
 		to_create = 1;
 	}
 
@@ -377,6 +378,8 @@ int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 		goto end;
 	}
 
+	uevent->enabled = 1;
+
 	switch (domain) {
 	case LTTNG_DOMAIN_UST:
 	{
@@ -407,10 +410,9 @@ int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 		goto end;
 	}
 
-	uevent->enabled = 1;
-	/* Add ltt ust event to channel */
 	if (to_create) {
 		rcu_read_lock();
+		/* Add ltt ust event to channel */
 		lttng_ht_add_unique_str(uchan->events, &uevent->node);
 		rcu_read_unlock();
 	}
@@ -418,11 +420,23 @@ int event_ust_enable_tracepoint(struct ltt_ust_session *usess, int domain,
 	DBG("Event UST %s %s in channel %s", uevent->attr.name,
 			to_create ? "created" : "enabled", uchan->name);
 
+	ret = LTTCOMM_OK;
+
 end:
-	return LTTCOMM_OK;
+	return ret;
 
 error:
-	trace_ust_destroy_event(uevent);
+	/*
+	 * Only destroy event on creation time (not enabling time) because if the
+	 * event is found in the channel (to_create == 0), it means that at some
+	 * point the enable_event worked and it's thus valid to keep it alive.
+	 * Destroying it also implies that we also destroy it's shadow copy to sync
+	 * everyone up.
+	 */
+	if (to_create) {
+		/* In this code path, the uevent was not added to the hash table */
+		trace_ust_destroy_event(uevent);
+	}
 	return ret;
 }