X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fconsumer.c;h=8b43257bd134987a3d0811320276010b724579b3;hp=f4eaf705f0b811230d0a9bb1f2f74458c7f7e6d0;hb=4bb94b7597f56f5200ebd6a88e906488172241fb;hpb=c30aaa51f34105a7f20b9ceb39866001843db6e6

diff --git a/src/common/consumer.c b/src/common/consumer.c
index f4eaf705f..8b43257bd 100644
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -62,20 +62,23 @@ volatile int consumer_quit = 0;
  * Find a stream. The consumer_data.lock must be locked during this
  * call.
  */
-static struct lttng_consumer_stream *consumer_find_stream(int key)
+static struct lttng_consumer_stream *consumer_find_stream(int key,
+		struct lttng_ht *ht)
 {
 	struct lttng_ht_iter iter;
 	struct lttng_ht_node_ulong *node;
 	struct lttng_consumer_stream *stream = NULL;
 
+	assert(ht);
+
 	/* Negative keys are lookup failures */
-	if (key < 0)
+	if (key < 0) {
 		return NULL;
+	}
 
 	rcu_read_lock();
 
-	lttng_ht_lookup(consumer_data.stream_ht, (void *)((unsigned long) key),
-			&iter);
+	lttng_ht_lookup(ht, (void *)((unsigned long) key), &iter);
 	node = lttng_ht_iter_get_node_ulong(&iter);
 	if (node != NULL) {
 		stream = caa_container_of(node, struct lttng_consumer_stream, node);
@@ -86,12 +89,12 @@ static struct lttng_consumer_stream *consumer_find_stream(int key)
 	return stream;
 }
 
-static void consumer_steal_stream_key(int key)
+static void consumer_steal_stream_key(int key, struct lttng_ht *ht)
 {
 	struct lttng_consumer_stream *stream;
 
 	rcu_read_lock();
-	stream = consumer_find_stream(key);
+	stream = consumer_find_stream(key, ht);
 	if (stream) {
 		stream->key = -1;
 		/*
@@ -111,8 +114,9 @@ static struct lttng_consumer_channel *consumer_find_channel(int key)
 	struct lttng_consumer_channel *channel = NULL;
 
 	/* Negative keys are lookup failures */
-	if (key < 0)
+	if (key < 0) {
 		return NULL;
+	}
 
 	rcu_read_lock();
 
@@ -157,6 +161,17 @@ void consumer_free_stream(struct rcu_head *head)
 	free(stream);
 }
 
+static
+void consumer_free_metadata_stream(struct rcu_head *head)
+{
+	struct lttng_ht_node_ulong *node =
+		caa_container_of(head, struct lttng_ht_node_ulong, head);
+	struct lttng_consumer_stream *stream =
+		caa_container_of(node, struct lttng_consumer_stream, waitfd_node);
+
+	free(stream);
+}
+
 /*
  * RCU protected relayd socket pair free.
  */
@@ -226,7 +241,8 @@ void consumer_flag_relayd_for_destroy(struct consumer_relayd_sock_pair *relayd)
  * Remove a stream from the global list protected by a mutex. This
  * function is also responsible for freeing its data structures.
  */
-void consumer_del_stream(struct lttng_consumer_stream *stream)
+void consumer_del_stream(struct lttng_consumer_stream *stream,
+		struct lttng_ht *ht)
 {
 	int ret;
 	struct lttng_ht_iter iter;
@@ -235,6 +251,11 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
 
 	assert(stream);
 
+	if (ht == NULL) {
+		/* Means the stream was allocated but not successfully added */
+		goto free_stream;
+	}
+
 	pthread_mutex_lock(&consumer_data.lock);
 
 	switch (consumer_data.type) {
@@ -242,7 +263,7 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
 		if (stream->mmap_base != NULL) {
 			ret = munmap(stream->mmap_base, stream->mmap_len);
 			if (ret != 0) {
-				perror("munmap");
+				PERROR("munmap");
 			}
 		}
 		break;
@@ -258,7 +279,7 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
 
 	rcu_read_lock();
 	iter.iter.node = &stream->node.node;
-	ret = lttng_ht_del(consumer_data.stream_ht, &iter);
+	ret = lttng_ht_del(ht, &iter);
 	assert(!ret);
 
 	rcu_read_unlock();
@@ -325,7 +346,6 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
 		free_chan = stream->chan;
 	}
 
-	call_rcu(&stream->node.head, consumer_free_stream);
 end:
 	consumer_data.need_update = 1;
 	pthread_mutex_unlock(&consumer_data.lock);
@@ -333,6 +353,9 @@ end:
 	if (free_chan) {
 		consumer_del_channel(free_chan);
 	}
+
+free_stream:
+	call_rcu(&stream->node.head, consumer_free_stream);
 }
 
 struct lttng_consumer_stream *consumer_allocate_stream(
@@ -345,22 +368,29 @@ struct lttng_consumer_stream *consumer_allocate_stream(
 		uid_t uid,
 		gid_t gid,
 		int net_index,
-		int metadata_flag)
+		int metadata_flag,
+		int *alloc_ret)
 {
 	struct lttng_consumer_stream *stream;
-	int ret;
 
 	stream = zmalloc(sizeof(*stream));
 	if (stream == NULL) {
-		perror("malloc struct lttng_consumer_stream");
+		PERROR("malloc struct lttng_consumer_stream");
+		*alloc_ret = -ENOMEM;
 		goto end;
 	}
+
+	/*
+	 * Get stream's channel reference. Needed when adding the stream to the
+	 * global hash table.
+	 */
 	stream->chan = consumer_find_channel(channel_key);
 	if (!stream->chan) {
-		perror("Unable to find channel key");
-		goto end;
+		*alloc_ret = -ENOENT;
+		ERR("Unable to find channel for stream %d", stream_key);
+		goto error;
 	}
-	stream->chan->refcount++;
+
 	stream->key = stream_key;
 	stream->shm_fd = shm_fd;
 	stream->wait_fd = wait_fd;
@@ -376,46 +406,20 @@ struct lttng_consumer_stream *consumer_allocate_stream(
 	stream->metadata_flag = metadata_flag;
 	strncpy(stream->path_name, path_name, sizeof(stream->path_name));
 	stream->path_name[sizeof(stream->path_name) - 1] = '\0';
-	lttng_ht_node_init_ulong(&stream->node, stream->key);
 	lttng_ht_node_init_ulong(&stream->waitfd_node, stream->wait_fd);
-
-	switch (consumer_data.type) {
-	case LTTNG_CONSUMER_KERNEL:
-		break;
-	case LTTNG_CONSUMER32_UST:
-	case LTTNG_CONSUMER64_UST:
-		stream->cpu = stream->chan->cpucount++;
-		ret = lttng_ustconsumer_allocate_stream(stream);
-		if (ret) {
-			free(stream);
-			return NULL;
-		}
-		break;
-	default:
-		ERR("Unknown consumer_data type");
-		assert(0);
-		goto end;
-	}
-
-	/*
-	 * When nb_init_streams reaches 0, we don't need to trigger any action in
-	 * terms of destroying the associated channel, because the action that
-	 * causes the count to become 0 also causes a stream to be added. The
-	 * channel deletion will thus be triggered by the following removal of this
-	 * stream.
-	 */
-	if (uatomic_read(&stream->chan->nb_init_streams) > 0) {
-		uatomic_dec(&stream->chan->nb_init_streams);
-	}
+	lttng_ht_node_init_ulong(&stream->node, stream->key);
 
 	DBG3("Allocated stream %s (key %d, shm_fd %d, wait_fd %d, mmap_len %llu,"
 			" out_fd %d, net_seq_idx %d)", stream->path_name, stream->key,
 			stream->shm_fd, stream->wait_fd,
 			(unsigned long long) stream->mmap_len, stream->out_fd,
 			stream->net_seq_idx);
+	return stream;
 
+error:
+	free(stream);
 end:
-	return stream;
+	return NULL;
 }
 
 /*
@@ -424,22 +428,35 @@ end:
 int consumer_add_stream(struct lttng_consumer_stream *stream)
 {
 	int ret = 0;
-	struct lttng_ht_node_ulong *node;
-	struct lttng_ht_iter iter;
 	struct consumer_relayd_sock_pair *relayd;
 
-	pthread_mutex_lock(&consumer_data.lock);
-	/* Steal stream identifier, for UST */
-	consumer_steal_stream_key(stream->key);
+	assert(stream);
+
+	DBG3("Adding consumer stream %d", stream->key);
 
+	pthread_mutex_lock(&consumer_data.lock);
 	rcu_read_lock();
-	lttng_ht_lookup(consumer_data.stream_ht,
-			(void *)((unsigned long) stream->key), &iter);
-	node = lttng_ht_iter_get_node_ulong(&iter);
-	if (node != NULL) {
-		rcu_read_unlock();
-		/* Stream already exist. Ignore the insertion */
-		goto end;
+
+	switch (consumer_data.type) {
+	case LTTNG_CONSUMER_KERNEL:
+		break;
+	case LTTNG_CONSUMER32_UST:
+	case LTTNG_CONSUMER64_UST:
+		stream->cpu = stream->chan->cpucount++;
+		ret = lttng_ustconsumer_add_stream(stream);
+		if (ret) {
+			ret = -EINVAL;
+			goto error;
+		}
+
+		/* Steal stream identifier only for UST */
+		consumer_steal_stream_key(stream->key, consumer_data.stream_ht);
+		break;
+	default:
+		ERR("Unknown consumer_data type");
+		assert(0);
+		ret = -ENOSYS;
+		goto error;
 	}
 
 	lttng_ht_add_unique_ulong(consumer_data.stream_ht, &stream->node);
@@ -449,13 +466,27 @@ int consumer_add_stream(struct lttng_consumer_stream *stream)
 	if (relayd != NULL) {
 		uatomic_inc(&relayd->refcount);
 	}
-	rcu_read_unlock();
 
-	/* Update consumer data */
+	/* Update channel refcount once added without error(s). */
+	uatomic_inc(&stream->chan->refcount);
+
+	/*
+	 * When nb_init_streams reaches 0, we don't need to trigger any action in
+	 * terms of destroying the associated channel, because the action that
+	 * causes the count to become 0 also causes a stream to be added. The
+	 * channel deletion will thus be triggered by the following removal of this
+	 * stream.
+	 */
+	if (uatomic_read(&stream->chan->nb_init_streams) > 0) {
+		uatomic_dec(&stream->chan->nb_init_streams);
+	}
+
+	/* Update consumer data once the node is inserted. */
 	consumer_data.stream_count++;
 	consumer_data.need_update = 1;
 
-end:
+error:
+	rcu_read_unlock();
 	pthread_mutex_unlock(&consumer_data.lock);
 
 	return ret;
@@ -607,7 +638,7 @@ void consumer_change_stream_state(int stream_key,
 	struct lttng_consumer_stream *stream;
 
 	pthread_mutex_lock(&consumer_data.lock);
-	stream = consumer_find_stream(stream_key);
+	stream = consumer_find_stream(stream_key, consumer_data.stream_ht);
 	if (stream) {
 		stream->state = state;
 	}
@@ -659,7 +690,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 	if (channel->mmap_base != NULL) {
 		ret = munmap(channel->mmap_base, channel->mmap_len);
 		if (ret != 0) {
-			perror("munmap");
+			PERROR("munmap");
 		}
 	}
 	if (channel->wait_fd >= 0 && !channel->wait_fd_is_copy) {
@@ -692,7 +723,7 @@ struct lttng_consumer_channel *consumer_allocate_channel(
 
 	channel = zmalloc(sizeof(*channel));
 	if (channel == NULL) {
-		perror("malloc struct lttng_consumer_channel");
+		PERROR("malloc struct lttng_consumer_channel");
 		goto end;
 	}
 	channel->key = channel_key;
@@ -816,7 +847,7 @@ restart:
 		if (errno == EINTR) {
 			goto restart;
 		}
-		perror("Poll error");
+		PERROR("Poll error");
 		goto exit;
 	}
 	if (consumer_sockpoll[0].revents & (POLLIN | POLLPRI)) {
@@ -881,7 +912,7 @@ void lttng_consumer_cleanup(void)
 			node) {
 		struct lttng_consumer_stream *stream =
 			caa_container_of(node, struct lttng_consumer_stream, node);
-		consumer_del_stream(stream);
+		consumer_del_stream(stream, consumer_data.stream_ht);
 	}
 
 	cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter, node,
@@ -908,7 +939,7 @@ void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx)
 		ret = write(ctx->consumer_should_quit[1], "4", 1);
 	} while (ret < 0 && errno == EINTR);
 	if (ret < 0) {
-		perror("write consumer quit");
+		PERROR("write consumer quit");
 	}
 }
 
@@ -980,7 +1011,7 @@ struct lttng_consumer_local_data *lttng_consumer_create(
 
 	ctx = zmalloc(sizeof(struct lttng_consumer_local_data));
 	if (ctx == NULL) {
-		perror("allocating context");
+		PERROR("allocating context");
 		goto error;
 	}
 
@@ -993,33 +1024,33 @@ struct lttng_consumer_local_data *lttng_consumer_create(
 
 	ret = pipe(ctx->consumer_poll_pipe);
 	if (ret < 0) {
-		perror("Error creating poll pipe");
+		PERROR("Error creating poll pipe");
 		goto error_poll_pipe;
 	}
 
 	/* set read end of the pipe to non-blocking */
 	ret = fcntl(ctx->consumer_poll_pipe[0], F_SETFL, O_NONBLOCK);
 	if (ret < 0) {
-		perror("fcntl O_NONBLOCK");
+		PERROR("fcntl O_NONBLOCK");
 		goto error_poll_fcntl;
 	}
 
 	/* set write end of the pipe to non-blocking */
 	ret = fcntl(ctx->consumer_poll_pipe[1], F_SETFL, O_NONBLOCK);
 	if (ret < 0) {
-		perror("fcntl O_NONBLOCK");
+		PERROR("fcntl O_NONBLOCK");
 		goto error_poll_fcntl;
 	}
 
 	ret = pipe(ctx->consumer_should_quit);
 	if (ret < 0) {
-		perror("Error creating recv pipe");
+		PERROR("Error creating recv pipe");
 		goto error_quit_pipe;
 	}
 
 	ret = pipe(ctx->consumer_thread_pipe);
 	if (ret < 0) {
-		perror("Error creating thread pipe");
+		PERROR("Error creating thread pipe");
 		goto error_thread_pipe;
 	}
 
@@ -1503,9 +1534,9 @@ int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 }
 
 /*
- * Iterate over all stream element of the hashtable and free them. This is race
- * free since the hashtable received MUST be in a race free synchronization
- * state. It's the caller responsability to make sure of that.
+ * Iterate over all streams of the hashtable and free them properly.
+ *
+ * XXX: Should not be only for metadata stream or else use an other name.
  */
 static void destroy_stream_ht(struct lttng_ht *ht)
 {
@@ -1518,11 +1549,11 @@ static void destroy_stream_ht(struct lttng_ht *ht)
 	}
 
 	rcu_read_lock();
-	cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
+	cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, waitfd_node.node) {
 		ret = lttng_ht_del(ht, &iter);
 		assert(!ret);
 
-		free(stream);
+		call_rcu(&stream->waitfd_node.head, consumer_free_metadata_stream);
 	}
 	rcu_read_unlock();
 
@@ -1532,9 +1563,12 @@ static void destroy_stream_ht(struct lttng_ht *ht)
 /*
  * Clean up a metadata stream and free its memory.
  */
-static void consumer_del_metadata_stream(struct lttng_consumer_stream *stream)
+void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
+		struct lttng_ht *ht)
 {
 	int ret;
+	struct lttng_ht_iter iter;
+	struct lttng_consumer_channel *free_chan = NULL;
 	struct consumer_relayd_sock_pair *relayd;
 
 	assert(stream);
@@ -1544,6 +1578,19 @@ static void consumer_del_metadata_stream(struct lttng_consumer_stream *stream)
 	 */
 	assert(stream->metadata_flag);
 
+	DBG3("Consumer delete metadata stream %d", stream->wait_fd);
+
+	if (ht == NULL) {
+		/* Means the stream was allocated but not successfully added */
+		goto free_stream;
+	}
+
+	rcu_read_lock();
+	iter.iter.node = &stream->waitfd_node.node;
+	ret = lttng_ht_del(ht, &iter);
+	assert(!ret);
+	rcu_read_unlock();
+
 	pthread_mutex_lock(&consumer_data.lock);
 	switch (consumer_data.type) {
 	case LTTNG_CONSUMER_KERNEL:
@@ -1561,8 +1608,8 @@ static void consumer_del_metadata_stream(struct lttng_consumer_stream *stream)
 	default:
 		ERR("Unknown consumer_data type");
 		assert(0);
+		goto end;
 	}
-	pthread_mutex_unlock(&consumer_data.lock);
 
 	if (stream->out_fd >= 0) {
 		ret = close(stream->out_fd);
@@ -1619,27 +1666,90 @@ static void consumer_del_metadata_stream(struct lttng_consumer_stream *stream)
 	if (!uatomic_read(&stream->chan->refcount)
 			&& !uatomic_read(&stream->chan->nb_init_streams)) {
 		/* Go for channel deletion! */
-		consumer_del_channel(stream->chan);
+		free_chan = stream->chan;
 	}
 
-	free(stream);
+end:
+	pthread_mutex_unlock(&consumer_data.lock);
+
+	if (free_chan) {
+		consumer_del_channel(free_chan);
+	}
+
+free_stream:
+	call_rcu(&stream->waitfd_node.head, consumer_free_metadata_stream);
 }
 
 /*
  * Action done with the metadata stream when adding it to the consumer internal
  * data structures to handle it.
  */
-static void consumer_add_metadata_stream(struct lttng_consumer_stream *stream)
+static int consumer_add_metadata_stream(struct lttng_consumer_stream *stream,
+		struct lttng_ht *ht)
 {
+	int ret = 0;
 	struct consumer_relayd_sock_pair *relayd;
 
-	/* Find relayd and, if one is found, increment refcount. */
+	assert(stream);
+	assert(ht);
+
+	DBG3("Adding metadata stream %d to hash table", stream->wait_fd);
+
+	pthread_mutex_lock(&consumer_data.lock);
+
+	switch (consumer_data.type) {
+	case LTTNG_CONSUMER_KERNEL:
+		break;
+	case LTTNG_CONSUMER32_UST:
+	case LTTNG_CONSUMER64_UST:
+		ret = lttng_ustconsumer_add_stream(stream);
+		if (ret) {
+			ret = -EINVAL;
+			goto error;
+		}
+
+		/* Steal stream identifier only for UST */
+		consumer_steal_stream_key(stream->wait_fd, ht);
+		break;
+	default:
+		ERR("Unknown consumer_data type");
+		assert(0);
+		ret = -ENOSYS;
+		goto error;
+	}
+
+	/*
+	 * From here, refcounts are updated so be _careful_ when returning an error
+	 * after this point.
+	 */
+
 	rcu_read_lock();
+	/* Find relayd and, if one is found, increment refcount. */
 	relayd = consumer_find_relayd(stream->net_seq_idx);
 	if (relayd != NULL) {
 		uatomic_inc(&relayd->refcount);
 	}
+
+	/* Update channel refcount once added without error(s). */
+	uatomic_inc(&stream->chan->refcount);
+
+	/*
+	 * When nb_init_streams reaches 0, we don't need to trigger any action in
+	 * terms of destroying the associated channel, because the action that
+	 * causes the count to become 0 also causes a stream to be added. The
+	 * channel deletion will thus be triggered by the following removal of this
+	 * stream.
+	 */
+	if (uatomic_read(&stream->chan->nb_init_streams) > 0) {
+		uatomic_dec(&stream->chan->nb_init_streams);
+	}
+
+	lttng_ht_add_unique_ulong(ht, &stream->waitfd_node);
 	rcu_read_unlock();
+
+error:
+	pthread_mutex_unlock(&consumer_data.lock);
+	return ret;
 }
 
 /*
@@ -1650,7 +1760,7 @@ void *lttng_consumer_thread_poll_metadata(void *data)
 {
 	int ret, i, pollfd;
 	uint32_t revents, nb_fd;
-	struct lttng_consumer_stream *stream;
+	struct lttng_consumer_stream *stream = NULL;
 	struct lttng_ht_iter iter;
 	struct lttng_ht_node_ulong *node;
 	struct lttng_ht *metadata_ht = NULL;
@@ -1698,16 +1808,22 @@ restart:
 		DBG("Metadata event catched in thread");
 		if (ret < 0) {
 			if (errno == EINTR) {
+				ERR("Poll EINTR catched");
 				goto restart;
 			}
 			goto error;
 		}
 
+		/* From here, the event is a metadata wait fd */
 		for (i = 0; i < nb_fd; i++) {
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			/* Check the metadata pipe for incoming metadata. */
+			/* Just don't waste time if no returned events for the fd */
+			if (!revents) {
+				continue;
+			}
+
 			if (pollfd == ctx->consumer_metadata_pipe[0]) {
 				if (revents & (LPOLLERR | LPOLLHUP )) {
 					DBG("Metadata thread pipe hung up");
@@ -1719,20 +1835,13 @@ restart:
 					close(ctx->consumer_metadata_pipe[0]);
 					continue;
 				} else if (revents & LPOLLIN) {
-					stream = zmalloc(sizeof(struct lttng_consumer_stream));
-					if (stream == NULL) {
-						PERROR("zmalloc metadata consumer stream");
-						goto error;
-					}
-
 					do {
-						/* Get the stream and add it to the local hash table */
-						ret = read(pollfd, stream,
-								sizeof(struct lttng_consumer_stream));
+						/* Get the stream pointer received */
+						ret = read(pollfd, &stream, sizeof(stream));
 					} while (ret < 0 && errno == EINTR);
-					if (ret < 0 || ret < sizeof(struct lttng_consumer_stream)) {
+					if (ret < 0 ||
+							ret < sizeof(struct lttng_consumer_stream *)) {
 						PERROR("read metadata stream");
-						free(stream);
 						/*
 						 * Let's continue here and hope we can still work
 						 * without stopping the consumer. XXX: Should we?
@@ -1743,40 +1852,61 @@ restart:
 					DBG("Adding metadata stream %d to poll set",
 							stream->wait_fd);
 
-					rcu_read_lock();
-					/* The node should be init at this point */
-					lttng_ht_add_unique_ulong(metadata_ht,
-							&stream->waitfd_node);
-					rcu_read_unlock();
+					ret = consumer_add_metadata_stream(stream, metadata_ht);
+					if (ret) {
+						ERR("Unable to add metadata stream");
+						/* Stream was not setup properly. Continuing. */
+						consumer_del_metadata_stream(stream, NULL);
+						continue;
+					}
 
 					/* Add metadata stream to the global poll events list */
 					lttng_poll_add(&events, stream->wait_fd,
 							LPOLLIN | LPOLLPRI);
-
-					consumer_add_metadata_stream(stream);
 				}
 
-				/* Metadata pipe handled. Continue handling the others */
+				/* Handle other stream */
 				continue;
 			}
 
-			/* From here, the event is a metadata wait fd */
-
 			rcu_read_lock();
 			lttng_ht_lookup(metadata_ht, (void *)((unsigned long) pollfd),
 					&iter);
 			node = lttng_ht_iter_get_node_ulong(&iter);
-			if (node == NULL) {
-				/* FD not found, continue loop */
-				rcu_read_unlock();
-				continue;
-			}
+			assert(node);
 
 			stream = caa_container_of(node, struct lttng_consumer_stream,
 					waitfd_node);
 
-			/* Get the data out of the metadata file descriptor */
-			if (revents & (LPOLLIN | LPOLLPRI)) {
+			/* Check for error event */
+			if (revents & (LPOLLERR | LPOLLHUP)) {
+				DBG("Metadata fd %d is hup|err.", pollfd);
+				if (!stream->hangup_flush_done
+						&& (consumer_data.type == LTTNG_CONSUMER32_UST
+							|| consumer_data.type == LTTNG_CONSUMER64_UST)) {
+					DBG("Attempting to flush and consume the UST buffers");
+					lttng_ustconsumer_on_stream_hangup(stream);
+
+					/* We just flushed the stream now read it. */
+					do {
+						len = ctx->on_buffer_ready(stream, ctx);
+						/*
+						 * We don't check the return value here since if we get
+						 * a negative len, it means an error occured thus we
+						 * simply remove it from the poll set and free the
+						 * stream.
+						 */
+					} while (len > 0);
+				}
+
+				lttng_poll_del(&events, stream->wait_fd);
+				/*
+				 * This call update the channel states, closes file descriptors
+				 * and securely free the stream.
+				 */
+				consumer_del_metadata_stream(stream, metadata_ht);
+			} else if (revents & (LPOLLIN | LPOLLPRI)) {
+				/* Get the data out of the metadata file descriptor */
 				DBG("Metadata available on fd %d", pollfd);
 				assert(stream->wait_fd == pollfd);
 
@@ -1790,33 +1920,7 @@ restart:
 				}
 			}
 
-			/*
-			 * Remove the stream from the hash table since there is no data
-			 * left on the fd because we previously did a read on the buffer.
-			 */
-			if (revents & (LPOLLERR | LPOLLHUP)) {
-				DBG("Metadata fd %d is hup|err|nval.", pollfd);
-				if (!stream->hangup_flush_done
-						&& (consumer_data.type == LTTNG_CONSUMER32_UST
-							|| consumer_data.type == LTTNG_CONSUMER64_UST)) {
-					DBG("Attempting to flush and consume the UST buffers");
-					lttng_ustconsumer_on_stream_hangup(stream);
-
-					/* We just flushed the stream now read it. */
-					len = ctx->on_buffer_ready(stream, ctx);
-					/* It's ok to have an unavailable sub-buffer */
-					if (len < 0 && len != -EAGAIN) {
-						rcu_read_unlock();
-						goto end;
-					}
-				}
-
-				/* Removing it from hash table, poll set and free memory */
-				lttng_ht_del(metadata_ht, &iter);
-
-				lttng_poll_del(&events, stream->wait_fd);
-				consumer_del_metadata_stream(stream);
-			}
+			/* Release RCU lock for the stream looked up */
 			rcu_read_unlock();
 		}
 	}
@@ -1885,7 +1989,7 @@ void *lttng_consumer_thread_poll_fds(void *data)
 			/* allocate for all fds + 1 for the consumer_poll_pipe */
 			pollfd = zmalloc((consumer_data.stream_count + 1) * sizeof(struct pollfd));
 			if (pollfd == NULL) {
-				perror("pollfd malloc");
+				PERROR("pollfd malloc");
 				pthread_mutex_unlock(&consumer_data.lock);
 				goto end;
 			}
@@ -1894,7 +1998,7 @@ void *lttng_consumer_thread_poll_fds(void *data)
 			local_stream = zmalloc((consumer_data.stream_count + 1) *
 					sizeof(struct lttng_consumer_stream));
 			if (local_stream == NULL) {
-				perror("local_stream malloc");
+				PERROR("local_stream malloc");
 				pthread_mutex_unlock(&consumer_data.lock);
 				goto end;
 			}
@@ -1926,7 +2030,7 @@ void *lttng_consumer_thread_poll_fds(void *data)
 			if (errno == EINTR) {
 				goto restart;
 			}
-			perror("Poll error");
+			PERROR("Poll error");
 			lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR);
 			goto end;
 		} else if (num_rdy == 0) {
@@ -2009,19 +2113,22 @@ void *lttng_consumer_thread_poll_fds(void *data)
 			if ((pollfd[i].revents & POLLHUP)) {
 				DBG("Polling fd %d tells it has hung up.", pollfd[i].fd);
 				if (!local_stream[i]->data_read) {
-					consumer_del_stream(local_stream[i]);
+					consumer_del_stream(local_stream[i],
+							consumer_data.stream_ht);
 					num_hup++;
 				}
 			} else if (pollfd[i].revents & POLLERR) {
 				ERR("Error returned in polling fd %d.", pollfd[i].fd);
 				if (!local_stream[i]->data_read) {
-					consumer_del_stream(local_stream[i]);
+					consumer_del_stream(local_stream[i],
+							consumer_data.stream_ht);
 					num_hup++;
 				}
 			} else if (pollfd[i].revents & POLLNVAL) {
 				ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
 				if (!local_stream[i]->data_read) {
-					consumer_del_stream(local_stream[i]);
+					consumer_del_stream(local_stream[i],
+							consumer_data.stream_ht);
 					num_hup++;
 				}
 			}
@@ -2098,7 +2205,7 @@ void *lttng_consumer_thread_receive_fds(void *data)
 
 	ret = fcntl(client_socket, F_SETFL, O_NONBLOCK);
 	if (ret < 0) {
-		perror("fcntl O_NONBLOCK");
+		PERROR("fcntl O_NONBLOCK");
 		goto end;
 	}
 
@@ -2121,7 +2228,7 @@ void *lttng_consumer_thread_receive_fds(void *data)
 	}
 	ret = fcntl(sock, F_SETFL, O_NONBLOCK);
 	if (ret < 0) {
-		perror("fcntl O_NONBLOCK");
+		PERROR("fcntl O_NONBLOCK");
 		goto end;
 	}