Fix: reverse channel and metadata cache lock nesting order

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

diff --git a/src/common/consumer/consumer.c b/src/common/consumer/consumer.c
index 234944dad0abf6d6c6594fa68ea64721f1488d87..89dad5917884fd986376107d8189efe8039fbe85 100644 (file)
--- a/src/common/consumer/consumer.c
+++ b/src/common/consumer/consumer.c
@@ -2051,8 +2051,11 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
        DBG3("Consumer delete metadata stream %d", stream->wait_fd);
 
        pthread_mutex_lock(&consumer_data.lock);
-       pthread_mutex_lock(&stream->chan->metadata_cache->lock);
        pthread_mutex_lock(&stream->chan->lock);
+       if (stream->chan->metadata_cache) {
+               /* Only applicable to userspace consumers. */
+               pthread_mutex_lock(&stream->chan->metadata_cache->lock);
+       }
        pthread_mutex_lock(&stream->lock);
 
        /* Remove any reference to that stream. */
@@ -2078,8 +2081,10 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
        stream->chan->metadata_stream = NULL;
 
        pthread_mutex_unlock(&stream->lock);
+       if (stream->chan->metadata_cache) {
+               pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
+       }
        pthread_mutex_unlock(&stream->chan->lock);
-       pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
        if (free_chan) {