Fix: holding the stream lock does not equate to having data pending

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

diff --git a/src/common/consumer/consumer.c b/src/common/consumer/consumer.c
index c2a2b1587ae6500039dcdddbbedc6eb41fa047b0..7b87a85fe600a21503177de42842b4a1e878bf3e 100644 (file)
--- a/src/common/consumer/consumer.c
+++ b/src/common/consumer/consumer.c
@@ -320,6 +320,7 @@ static void free_relayd_rcu(struct rcu_head *head)
        (void) relayd_close(&relayd->control_sock);
        (void) relayd_close(&relayd->data_sock);
 
+       pthread_mutex_destroy(&relayd->ctrl_sock_mutex);
        free(relayd);
 }
 
@@ -791,13 +792,12 @@ int consumer_send_relayd_stream(struct lttng_consumer_stream *stream,
                ret = relayd_add_stream(&relayd->control_sock, stream->name,
                                path, &stream->relayd_stream_id,
                                stream->chan->tracefile_size, stream->chan->tracefile_count);
+               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                if (ret < 0) {
                        ERR("Relayd add stream failed. Cleaning up relayd %" PRIu64".", relayd->net_seq_idx);
                        lttng_consumer_cleanup_relayd(relayd);
-                       pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        goto end;
                }
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 
                uatomic_inc(&relayd->refcount);
                stream->sent_to_relayd = 1;
@@ -835,13 +835,12 @@ int consumer_send_relayd_streams_sent(uint64_t net_seq_idx)
                /* Add stream on the relayd */
                pthread_mutex_lock(&relayd->ctrl_sock_mutex);
                ret = relayd_streams_sent(&relayd->control_sock);
+               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                if (ret < 0) {
                        ERR("Relayd streams sent failed. Cleaning up relayd %" PRIu64".", relayd->net_seq_idx);
                        lttng_consumer_cleanup_relayd(relayd);
-                       pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        goto end;
                }
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
        } else {
                ERR("Relayd ID %" PRIu64 " unknown. Can't send streams_sent.",
                                net_seq_idx);
@@ -3539,34 +3538,6 @@ error_nosignal:
        return ret;
 }
 
-/*
- * Try to lock the stream mutex.
- *
- * On success, 1 is returned else 0 indicating that the mutex is NOT lock.
- */
-static int stream_try_lock(struct lttng_consumer_stream *stream)
-{
-       int ret;
-
-       assert(stream);
-
-       /*
-        * Try to lock the stream mutex. On failure, we know that the stream is
-        * being used else where hence there is data still being extracted.
-        */
-       ret = pthread_mutex_trylock(&stream->lock);
-       if (ret) {
-               /* For both EBUSY and EINVAL error, the mutex is NOT locked. */
-               ret = 0;
-               goto end;
-       }
-
-       ret = 1;
-
-end:
-       return ret;
-}
-
 /*
  * Search for a relayd associated to the session id and return the reference.
  *
@@ -3639,25 +3610,20 @@ int consumer_data_pending(uint64_t id)
                pthread_mutex_lock(&relayd->ctrl_sock_mutex);
                ret = relayd_begin_data_pending(&relayd->control_sock,
                                relayd->relayd_session_id);
+               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                if (ret < 0) {
                        /* Communication error thus the relayd so no data pending. */
                        ERR("Relayd begin data pending failed. Cleaning up relayd %" PRIu64".", relayd->net_seq_idx);
                        lttng_consumer_cleanup_relayd(relayd);
-                       pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        goto data_not_pending;
                }
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
        }
 
        cds_lfht_for_each_entry_duplicate(ht->ht,
                        ht->hash_fct(&id, lttng_ht_seed),
                        ht->match_fct, &id,
                        &iter.iter, stream, node_session_id.node) {
-               /* If this call fails, the stream is being used hence data pending. */
-               ret = stream_try_lock(stream);
-               if (!ret) {
-                       goto data_pending;
-               }
+               pthread_mutex_lock(&stream->lock);
 
                /*
                 * A removed node from the hash table indicates that the stream has
@@ -3709,13 +3675,12 @@ int consumer_data_pending(uint64_t id)
                pthread_mutex_lock(&relayd->ctrl_sock_mutex);
                ret = relayd_end_data_pending(&relayd->control_sock,
                                relayd->relayd_session_id, &is_data_inflight);
+               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                if (ret < 0) {
                        ERR("Relayd end data pending failed. Cleaning up relayd %" PRIu64".", relayd->net_seq_idx);
                        lttng_consumer_cleanup_relayd(relayd);
-                       pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        goto data_not_pending;
                }
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                if (is_data_inflight) {
                        goto data_pending;
                }