Fix: Missing rcu read side lock in consumer
[lttng-tools.git] / src / common / consumer.c
index 72c820d90a11ec11d61e2e9024cb8f44f1ad009e..a2980e77d29c33b57c4a12889cb82db019956fa0 100644 (file)
@@ -175,7 +175,7 @@ static void consumer_rcu_free_relayd(struct rcu_head *head)
  *
  * This function MUST be called with the consumer_data lock acquired.
  */
-void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd)
+static void destroy_relayd(struct consumer_relayd_sock_pair *relayd)
 {
        int ret;
        struct lttng_ht_iter iter;
@@ -218,7 +218,7 @@ void consumer_flag_relayd_for_destroy(struct consumer_relayd_sock_pair *relayd)
 
        /* Destroy the relayd if refcount is 0 */
        if (uatomic_read(&relayd->refcount) == 0) {
-               consumer_destroy_relayd(relayd);
+               destroy_relayd(relayd);
        }
 }
 
@@ -314,7 +314,7 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
                /* Both conditions are met, we destroy the relayd. */
                if (uatomic_read(&relayd->refcount) == 0 &&
                                uatomic_read(&relayd->destroy_flag)) {
-                       consumer_destroy_relayd(relayd);
+                       destroy_relayd(relayd);
                }
        }
        rcu_read_unlock();
@@ -452,8 +452,7 @@ end:
  * Add relayd socket to global consumer data hashtable. RCU read side lock MUST
  * be acquired before calling this.
  */
-
-int consumer_add_relayd(struct consumer_relayd_sock_pair *relayd)
+static int add_relayd(struct consumer_relayd_sock_pair *relayd)
 {
        int ret = 0;
        struct lttng_ht_node_ulong *node;
@@ -1503,12 +1502,14 @@ static void destroy_stream_ht(struct lttng_ht *ht)
                return;
        }
 
+       rcu_read_lock();
        cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
                ret = lttng_ht_del(ht, &iter);
                assert(!ret);
 
                free(stream);
        }
+       rcu_read_unlock();
 
        lttng_ht_destroy(ht);
 }
@@ -1594,7 +1595,7 @@ static void consumer_del_metadata_stream(struct lttng_consumer_stream *stream)
                /* Both conditions are met, we destroy the relayd. */
                if (uatomic_read(&relayd->refcount) == 0 &&
                                uatomic_read(&relayd->destroy_flag)) {
-                       consumer_destroy_relayd(relayd);
+                       destroy_relayd(relayd);
                }
        }
        rcu_read_unlock();
@@ -1730,9 +1731,11 @@ restart:
                                        DBG("Adding metadata stream %d to poll set",
                                                        stream->wait_fd);
 
+                                       rcu_read_lock();
                                        /* The node should be init at this point */
                                        lttng_ht_add_unique_ulong(metadata_ht,
                                                        &stream->waitfd_node);
+                                       rcu_read_unlock();
 
                                        /* Add metadata stream to the global poll events list */
                                        lttng_poll_add(&events, stream->wait_fd,
@@ -1747,11 +1750,13 @@ restart:
 
                        /* From here, the event is a metadata wait fd */
 
+                       rcu_read_lock();
                        lttng_ht_lookup(metadata_ht, (void *)((unsigned long) pollfd),
                                        &iter);
                        node = lttng_ht_iter_get_node_ulong(&iter);
                        if (node == NULL) {
                                /* FD not found, continue loop */
+                               rcu_read_unlock();
                                continue;
                        }
 
@@ -1766,6 +1771,7 @@ restart:
                                len = ctx->on_buffer_ready(stream, ctx);
                                /* It's ok to have an unavailable sub-buffer */
                                if (len < 0 && len != -EAGAIN) {
+                                       rcu_read_unlock();
                                        goto end;
                                } else if (len > 0) {
                                        stream->data_read = 1;
@@ -1788,15 +1794,18 @@ restart:
                                        len = ctx->on_buffer_ready(stream, ctx);
                                        /* It's ok to have an unavailable sub-buffer */
                                        if (len < 0 && len != -EAGAIN) {
+                                               rcu_read_unlock();
                                                goto end;
                                        }
                                }
 
                                /* Removing it from hash table, poll set and free memory */
                                lttng_ht_del(metadata_ht, &iter);
+
                                lttng_poll_del(&events, stream->wait_fd);
                                consumer_del_metadata_stream(stream);
                        }
+                       rcu_read_unlock();
                }
        }
 
@@ -2290,7 +2299,7 @@ int consumer_add_relayd_socket(int net_seq_idx, int sock_type,
         * Add relayd socket pair to consumer data hashtable. If object already
         * exists or on error, the function gracefully returns.
         */
-       consumer_add_relayd(relayd);
+       add_relayd(relayd);
 
        /* All good! */
        ret = 0;
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