Fix deadlock: don't take channel lock in timer

[lttng-tools.git] / src / common / consumer.c

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 57e26dcf86c869982e579e86b73ea3a663c75052..6cf85d96a75b0afa69994886d9a94d91a7faaa29 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -491,6 +491,7 @@ struct lttng_consumer_stream *consumer_allocate_stream(uint64_t channel_key,
        stream->net_seq_idx = relayd_id;
        stream->session_id = session_id;
        stream->monitor = monitor;
+       stream->endpoint_status = CONSUMER_ENDPOINT_ACTIVE;
        pthread_mutex_init(&stream->lock, NULL);
 
        /* If channel is the metadata, flag this stream as metadata. */
@@ -550,6 +551,7 @@ static int add_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
+       pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
        rcu_read_lock();
 
@@ -587,6 +589,7 @@ static int add_stream(struct lttng_consumer_stream *stream,
 
        rcu_read_unlock();
        pthread_mutex_unlock(&stream->lock);
+       pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&stream->chan->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -837,6 +840,7 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
        channel->tracefile_count = tracefile_count;
        channel->monitor = monitor;
        pthread_mutex_init(&channel->lock, NULL);
+       pthread_mutex_init(&channel->timer_lock, NULL);
 
        /*
         * In monitor mode, the streams associated with the channel will be put in
@@ -883,6 +887,7 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
        rcu_read_lock();
 
        lttng_ht_lookup(consumer_data.channel_ht, &channel->key, &iter);
@@ -899,6 +904,7 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
 
 end:
        rcu_read_unlock();
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -1152,6 +1158,7 @@ struct lttng_consumer_local_data *lttng_consumer_create(
 
        ctx->consumer_error_socket = -1;
        ctx->consumer_metadata_socket = -1;
+       pthread_mutex_init(&ctx->metadata_socket_lock, NULL);
        /* assign the callbacks */
        ctx->on_buffer_ready = buffer_ready;
        ctx->on_recv_channel = recv_channel;
@@ -1879,6 +1886,13 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
                break;
        case LTTNG_CONSUMER32_UST:
        case LTTNG_CONSUMER64_UST:
+               if (stream->monitor) {
+                       /* close the write-side in close_metadata */
+                       ret = close(stream->ust_metadata_poll_pipe[0]);
+                       if (ret < 0) {
+                               PERROR("Close UST metadata read-side poll pipe");
+                       }
+               }
                lttng_ustconsumer_del_stream(stream);
                break;
        default:
@@ -1947,8 +1961,8 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
 end:
        /*
         * Nullify the stream reference so it is not used after deletion. The
-        * consumer data lock MUST be acquired before being able to check for a
-        * NULL pointer value.
+        * channel lock MUST be acquired before being able to check for
+        * a NULL pointer value.
         */
        stream->chan->metadata_stream = NULL;
 
@@ -1982,6 +1996,7 @@ static int add_metadata_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
+       pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
 
        /*
@@ -2028,6 +2043,7 @@ static int add_metadata_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_unlock(&stream->lock);
        pthread_mutex_unlock(&stream->chan->lock);
+       pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&consumer_data.lock);
        return ret;
 }
@@ -2251,14 +2267,21 @@ restart:
                                DBG("Metadata available on fd %d", pollfd);
                                assert(stream->wait_fd == pollfd);
 
-                               len = ctx->on_buffer_ready(stream, ctx);
+                               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);
+
                                /* It's ok to have an unavailable sub-buffer */
                                if (len < 0 && len != -EAGAIN && len != -ENODATA) {
                                        /* Clean up stream from consumer and free it. */
                                        lttng_poll_del(&events, stream->wait_fd);
                                        consumer_del_metadata_stream(stream, metadata_ht);
-                               } else if (len > 0) {
-                                       stream->data_read = 1;
                                }
                        }