X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Ftrace-ust.c;h=0e386aa0327f2f430806321766e2a4e2516b64dc;hp=1f6fd52736abe4f8abde125fdc092601d491ec46;hb=6c1c0768320135c6936c371b09731851b508c023;hpb=1e199c04cd2f0b9c378d89a11e42c516d5f8d90e

diff --git a/src/bin/lttng-sessiond/trace-ust.c b/src/bin/lttng-sessiond/trace-ust.c
index 1f6fd5273..0e386aa03 100644
--- a/src/bin/lttng-sessiond/trace-ust.c
+++ b/src/bin/lttng-sessiond/trace-ust.c
@@ -16,6 +16,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -202,6 +203,9 @@ 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)
@@ -749,10 +753,12 @@ 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,