Fix: consumerd: crash occurs when taking snapshot of ust channel

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

diff --git a/src/common/consumer/consumer-metadata-cache.c b/src/common/consumer/consumer-metadata-cache.c
index 5eee4014265f42566776ea34645a0f08504fbde0..3fffe53397b368f57e9ddc1e81257bfb50342e94 100644 (file)
--- a/src/common/consumer/consumer-metadata-cache.c
+++ b/src/common/consumer/consumer-metadata-cache.c
@@ -274,16 +274,19 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
        }
        pthread_mutex_lock(&channel->timer_lock);
        metadata_stream = channel->metadata_stream;
-       pthread_mutex_lock(&metadata_stream->lock);
-       pthread_mutex_lock(&channel->metadata_cache->lock);
-
        if (!metadata_stream) {
                /*
                 * Having no metadata stream means the channel is being destroyed so there
                 * is no cache to flush anymore.
                 */
                ret = 0;
-       } else if (metadata_stream->ust_metadata_pushed >= offset) {
+               goto end_unlock_channel;
+       }
+
+       pthread_mutex_lock(&metadata_stream->lock);
+       pthread_mutex_lock(&channel->metadata_cache->lock);
+
+       if (metadata_stream->ust_metadata_pushed >= offset) {
                ret = 0;
        } else if (channel->metadata_stream->endpoint_status !=
                        CONSUMER_ENDPOINT_ACTIVE) {
@@ -296,6 +299,7 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
 
        pthread_mutex_unlock(&channel->metadata_cache->lock);
        pthread_mutex_unlock(&metadata_stream->lock);
+end_unlock_channel:
        pthread_mutex_unlock(&channel->timer_lock);
        if (!timer) {
                pthread_mutex_unlock(&channel->lock);