X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lttng-events.c;h=135c8c527123acd43266c7191148d9bc314121a8;hb=f4855b46cb97a7ad649e97232719c50ab8688119;hp=eefee69b31a5cc59583fb57d7f074c5715aec654;hpb=20591cf76d5dfd42d61a18bd494b40a70a04dd59;p=lttng-modules.git

diff --git a/lttng-events.c b/lttng-events.c
index eefee69b..135c8c52 100644
--- a/lttng-events.c
+++ b/lttng-events.c
@@ -98,6 +98,8 @@ struct lttng_session *lttng_session_create(void)
 	kref_init(&metadata_cache->refcount);
 	session->metadata_cache = metadata_cache;
 	INIT_LIST_HEAD(&metadata_cache->metadata_stream);
+	memcpy(&metadata_cache->uuid, &session->uuid,
+		sizeof(metadata_cache->uuid));
 	list_add(&session->list, &sessions);
 	mutex_unlock(&sessions_mutex);
 	return session;
@@ -377,8 +379,14 @@ struct lttng_event *lttng_event_create(struct lttng_channel *chan,
 	 */
 	list_for_each_entry(event, &chan->session->events, list) {
 		if (!strcmp(event->desc->name, event_param->name)) {
-			ret = -EEXIST;
-			goto exist;
+			/*
+			 * Allow events with the same name to appear in
+			 * different channels.
+			 */
+			if (event->chan == chan) {
+				ret = -EEXIST;
+				goto exist;
+			}
 		}
 	}
 	event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
@@ -597,16 +605,20 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
 
 	/*
 	 * Ensure we support mutiple get_next / put sequences followed
-	 * by put_next.
+	 * by put_next. The metadata stream lock internally protects
+	 * reading the metadata cache. It can indeed be read
+	 * concurrently by "get_next_subbuf" and "flush" operations on
+	 * the buffer invoked by different processes.
 	 */
+	mutex_lock(&stream->lock);
 	WARN_ON(stream->metadata_in < stream->metadata_out);
 	if (stream->metadata_in != stream->metadata_out)
-		return 0;
+		goto end;
 
 	len = stream->metadata_cache->metadata_written -
 		stream->metadata_in;
 	if (!len)
-		return 0;
+		goto end;
 	reserve_len = min_t(size_t,
 			stream->transport->ops.packet_avail_size(chan),
 			len);
@@ -628,6 +640,7 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
 	ret = reserve_len;
 
 end:
+	mutex_unlock(&stream->lock);
 	return ret;
 }
 
@@ -1255,6 +1268,10 @@ static int __init lttng_events_init(void)
 {
 	int ret;
 
+	ret = wrapper_lttng_fixup_sig(THIS_MODULE);
+	if (ret)
+		return ret;
+
 	ret = lttng_tracepoint_init();
 	if (ret)
 		return ret;