Fix: consumerd metadata channel/cache/timer races

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

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 03c00a677ac4f53702dd79c68cc2759b897bdd4f..031a7cb261a52fa8d6b0c4c53be291be5896b973 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -581,6 +581,7 @@ static int flush_channel(uint64_t chan_key)
 
        DBG("UST consumer flush channel key %" PRIu64, chan_key);
 
+       rcu_read_lock();
        channel = consumer_find_channel(chan_key);
        if (!channel) {
                ERR("UST consumer flush channel %" PRIu64 " not found", chan_key);
@@ -591,26 +592,25 @@ static int flush_channel(uint64_t chan_key)
        ht = consumer_data.stream_per_chan_id_ht;
 
        /* For each stream of the channel id, flush it. */
-       rcu_read_lock();
        cds_lfht_for_each_entry_duplicate(ht->ht,
                        ht->hash_fct(&channel->key, lttng_ht_seed), ht->match_fct,
                        &channel->key, &iter.iter, stream, node_channel_id.node) {
                        ustctl_flush_buffer(stream->ustream, 1);
        }
-       rcu_read_unlock();
-
 error:
+       rcu_read_unlock();
        return ret;
 }
 
 /*
  * Close metadata stream wakeup_fd using the given key to retrieve the channel.
+ * RCU read side lock MUST be acquired before calling this function.
  *
  * Return 0 on success else an LTTng error code.
  */
 static int close_metadata(uint64_t chan_key)
 {
-       int ret;
+       int ret = 0;
        struct lttng_consumer_channel *channel;
 
        DBG("UST consumer close metadata key %" PRIu64, chan_key);
@@ -622,18 +622,22 @@ static int close_metadata(uint64_t chan_key)
                goto error;
        }
 
-       ret = ustctl_stream_close_wakeup_fd(channel->metadata_stream->ustream);
-       if (ret < 0) {
-               ERR("UST consumer unable to close fd of metadata (ret: %d)", ret);
-               ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
-               goto error;
-       }
-       if (channel->switch_timer_enabled == 1) {
-               DBG("Deleting timer on metadata channel");
-               consumer_timer_switch_stop(channel);
+       pthread_mutex_lock(&consumer_data.lock);
+       if (!cds_lfht_is_node_deleted(&channel->node.node)) {
+               if (channel->switch_timer_enabled == 1) {
+                       DBG("Deleting timer on metadata channel");
+                       consumer_timer_switch_stop(channel);
+               }
+               ret = ustctl_stream_close_wakeup_fd(channel->metadata_stream->ustream);
+               if (ret < 0) {
+                       ERR("UST consumer unable to close fd of metadata (ret: %d)", ret);
+                       ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
+                       goto error_unlock;
+               }
        }
-       consumer_metadata_cache_destroy(channel);
 
+error_unlock:
+       pthread_mutex_unlock(&consumer_data.lock);
 error:
        return ret;
 }
@@ -923,10 +927,15 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                 */
                ret = add_channel(channel, ctx);
                if (ret < 0) {
+                       if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
+                               if (channel->switch_timer_enabled == 1) {
+                                       consumer_timer_switch_stop(channel);
+                               }
+                               consumer_metadata_cache_destroy(channel);
+                       }
                        goto end_channel_error;
                }
 
-
                /*
                 * Channel and streams are now created. Inform the session daemon that
                 * everything went well and should wait to receive the channel and
@@ -998,17 +1007,13 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        case LTTNG_CONSUMER_DESTROY_CHANNEL:
        {
                uint64_t key = msg.u.destroy_channel.key;
-               struct lttng_consumer_channel *channel;
-
-               channel = consumer_find_channel(key);
-               if (!channel) {
-                       ERR("UST consumer get channel key %" PRIu64 " not found", key);
-                       ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
-                       goto end_msg_sessiond;
-               }
-
-               destroy_channel(channel);
 
+               /*
+                * Only called if streams have not been sent to stream
+                * manager thread. However, channel has been sent to
+                * channel manager thread.
+                */
+               notify_thread_del_channel(ctx, key);
                goto end_msg_sessiond;
        }
        case LTTNG_CONSUMER_CLOSE_METADATA:
@@ -1197,6 +1202,10 @@ void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
        assert(chan);
        assert(chan->uchan);
 
+       if (chan->switch_timer_enabled == 1) {
+               consumer_timer_switch_stop(chan);
+       }
+       consumer_metadata_cache_destroy(chan);
        ustctl_destroy_channel(chan->uchan);
 }
 
@@ -1205,6 +1214,9 @@ void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
        assert(stream);
        assert(stream->ustream);
 
+       if (stream->chan->switch_timer_enabled == 1) {
+               consumer_timer_switch_stop(stream->chan);
+       }
        ustctl_destroy_stream(stream->ustream);
 }