From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 18 Nov 2014 19:09:36 +0000 (-0500)
Subject: Fix: Missing rcu_read_lock in save_domains()
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=65d72c41ed358620e40a7f6afb07e785e31c0d6a

Fix: Missing rcu_read_lock in save_domains()

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/save.c b/src/bin/lttng-sessiond/save.c
index b78e7f785..c6fc33e7b 100644
--- a/src/bin/lttng-sessiond/save.c
+++ b/src/bin/lttng-sessiond/save.c
@@ -1225,6 +1225,8 @@ int save_domains(struct config_writer *writer, struct ltt_session *session)
 	}
 
 	if (session->ust_session) {
+		unsigned long agent_count;
+
 		ret = config_writer_open_element(writer,
 			config_element_domain);
 		if (ret) {
@@ -1243,30 +1245,37 @@ int save_domains(struct config_writer *writer, struct ltt_session *session)
 			ret = LTTNG_ERR_SAVE_IO_FAIL;
 			goto end;
 		}
-	}
 
-	if (session->ust_session &&
-			lttng_ht_get_count(session->ust_session->agents) > 0) {
-		ret = config_writer_open_element(writer,
-			config_element_domain);
-		if (ret) {
-			ret = LTTNG_ERR_SAVE_IO_FAIL;
-			goto end;
-		}
+		rcu_read_lock();
+		agent_count =
+			lttng_ht_get_count(session->ust_session->agents);
+		rcu_read_unlock();
 
-		ret = save_ust_session(writer, session, 1);
-		if (ret) {
-			goto end;
-		}
+		if (agent_count > 0) {
+			ret = config_writer_open_element(writer,
+				config_element_domain);
+			if (ret) {
+				ret = LTTNG_ERR_SAVE_IO_FAIL;
+				goto end;
+			}
 
-		/* /domain */
-		ret = config_writer_close_element(writer);
-		if (ret) {
-			ret = LTTNG_ERR_SAVE_IO_FAIL;
-			goto end;
+			ret = save_ust_session(writer, session, 1);
+			if (ret) {
+				goto end;
+			}
+
+			/* /domain */
+			ret = config_writer_close_element(writer);
+			if (ret) {
+				ret = LTTNG_ERR_SAVE_IO_FAIL;
+				goto end;
+			}
 		}
 	}
 
+	if (session->ust_session) {
+	}
+
 	/* /domains */
 	ret = config_writer_close_element(writer);
 	if (ret) {