Fix: Missing rcu_read_lock in get_session_max_subbuf_size()

[lttng-tools.git] / src / bin / lttng-sessiond / trace-ust.c

diff --git a/src/bin/lttng-sessiond/trace-ust.c b/src/bin/lttng-sessiond/trace-ust.c
index 1f6fd52736abe4f8abde125fdc092601d491ec46..999f0dfc21e75f4e988476be894adcff3e33f4bc 100644 (file)
--- a/src/bin/lttng-sessiond/trace-ust.c
+++ b/src/bin/lttng-sessiond/trace-ust.c
@@ -202,6 +202,9 @@ error:
 /*
  * Lookup an agent in the session agents hash table by domain type and return
  * the object if found else NULL.
+ *
+ * RCU read side lock must be acquired before calling and only released
+ * once the agent is no longer in scope or being used.
  */
 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
                enum lttng_domain_type domain_type)
@@ -362,6 +365,7 @@ error:
 
 /*
  * Allocate and initialize a ust event. Set name and event type.
+ * We own filter_expression, filter, and exclusion.
  *
  * Return pointer to structure or NULL.
  */
@@ -419,6 +423,11 @@ struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
                ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
                goto error_free_event;
        }
+       /*
+        * Fix for enabler race. Enable is now done explicitly by
+        * sessiond after setting filter.
+        */
+       lue->attr.disabled = 1;
 
        /* Same layout. */
        lue->filter_expression = filter_expression;
@@ -437,6 +446,9 @@ struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
 error_free_event:
        free(lue);
 error:
+       free(filter_expression);
+       free(filter);
+       free(exclusion);
        return NULL;
 }
 
@@ -749,10 +761,12 @@ void trace_ust_destroy_session(struct ltt_ust_session *session)
        /* Cleaning up UST domain */
        destroy_domain_global(&session->domain_global);
 
+       rcu_read_lock();
        cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
                lttng_ht_del(session->agents, &iter);
                agent_destroy(agt);
        }
+       rcu_read_unlock();
 
        /* Cleanup UID buffer registry object(s). */
        cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,