Introduce channel timer lock

[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 21100dc648747ac132227cb4ea1438969e67a016..f9d0817c2de5f44c217b71920fdf2d08f5ae6abc 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -654,6 +654,7 @@ static int close_metadata(uint64_t chan_key)
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
 
        if (cds_lfht_is_node_deleted(&channel->node.node)) {
                goto error_unlock;
@@ -674,6 +675,7 @@ static int close_metadata(uint64_t chan_key)
        }
 
 error_unlock:
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 error:
@@ -779,6 +781,7 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
         */
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
        pthread_mutex_lock(&channel->metadata_cache->lock);
        ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
        if (ret < 0) {
@@ -790,11 +793,13 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
                 * waiting for the metadata cache to be flushed.
                 */
                pthread_mutex_unlock(&channel->metadata_cache->lock);
+               pthread_mutex_unlock(&channel->timer_lock);
                pthread_mutex_unlock(&channel->lock);
                pthread_mutex_unlock(&consumer_data.lock);
                goto end_free;
        }
        pthread_mutex_unlock(&channel->metadata_cache->lock);
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -1486,6 +1491,12 @@ void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
        }
 }
 
+/*
+ * Please refer to consumer-timer.c before adding any lock within this
+ * function or any of its callees. Timers have a very strict locking
+ * semantic with respect to teardown. Failure to respect this semantic
+ * introduces deadlocks.
+ */
 int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
                struct lttng_consumer_channel *channel)
 {