Fix deadlock: don't take channel lock in timer

[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 f9d0817c2de5f44c217b71920fdf2d08f5ae6abc..290eb3390e80aff424d954f8d9b7a00746f62fc0 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -654,7 +654,6 @@ 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;
@@ -675,7 +674,6 @@ 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:
@@ -748,7 +746,8 @@ error_find:
  * Receive the metadata updates from the sessiond.
  */
 int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
-               uint64_t len, struct lttng_consumer_channel *channel)
+               uint64_t len, struct lttng_consumer_channel *channel,
+               int timer)
 {
        int ret, ret_code = LTTNG_OK;
        char *metadata_str;
@@ -770,17 +769,9 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
                goto end_free;
        }
 
-       /*
-        * XXX: The consumer data lock is acquired before calling metadata cache
-        * write which calls push metadata that MUST be protected by the consumer
-        * lock in order to be able to check the validity of the metadata stream of
-        * the channel.
-        *
-        * Note that this will be subject to change to better fine grained locking
-        * and ultimately try to get rid of this global consumer data lock.
-        */
-       pthread_mutex_lock(&consumer_data.lock);
-       pthread_mutex_lock(&channel->lock);
+       if (!timer) {
+               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);
@@ -794,16 +785,18 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
                 */
                pthread_mutex_unlock(&channel->metadata_cache->lock);
                pthread_mutex_unlock(&channel->timer_lock);
-               pthread_mutex_unlock(&channel->lock);
-               pthread_mutex_unlock(&consumer_data.lock);
+               if (!timer) {
+                       pthread_mutex_unlock(&channel->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);
+       if (!timer) {
+               pthread_mutex_unlock(&channel->lock);
+       }
 
-       while (consumer_metadata_cache_flushed(channel, offset + len)) {
+       while (consumer_metadata_cache_flushed(channel, offset + len, timer)) {
                DBG("Waiting for metadata to be flushed");
                usleep(DEFAULT_METADATA_AVAILABILITY_WAIT_TIME);
        }
@@ -1139,7 +1132,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                }
 
                ret = lttng_ustconsumer_recv_metadata(sock, key, offset,
-                               len, channel);
+                               len, channel, 0);
                if (ret < 0) {
                        /* error receiving from sessiond */
                        goto error_fatal;
@@ -1498,7 +1491,7 @@ void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
  * introduces deadlocks.
  */
 int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_channel *channel)
+               struct lttng_consumer_channel *channel, int timer)
 {
        struct lttcomm_metadata_request_msg request;
        struct lttcomm_consumer_msg msg;
@@ -1585,7 +1578,7 @@ int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
        }
 
        ret_code = lttng_ustconsumer_recv_metadata(ctx->consumer_metadata_socket,
-                       key, offset, len, channel);
+                       key, offset, len, channel, timer);
        if (ret_code >= 0) {
                /*
                 * Only send the status msg if the sessiond is alive meaning a positive