From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Mon, 17 Aug 2020 20:55:39 +0000 (-0400)
Subject: Fix: sessiond: missing rcu read lock on client in/out events
X-Git-Tag: v2.13.0-rc1~492
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=98b5ff34df5d330fe139907ed77b4327ce9afa48

Fix: sessiond: missing rcu read lock on client in/out events

Users of get_client_from_sock() must hold the RCU read lock
for the duration of the use of the notification_client.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I644e549187ee47c959eeb692e27be111343d8979
---

diff --git a/src/bin/lttng-sessiond/notification-thread-events.c b/src/bin/lttng-sessiond/notification-thread-events.c
index de654a4ee..2a9423dcf 100644
--- a/src/bin/lttng-sessiond/notification-thread-events.c
+++ b/src/bin/lttng-sessiond/notification-thread-events.c
@@ -3189,6 +3189,7 @@ int handle_notification_thread_client_in(
 	size_t offset;
 	bool message_is_complete = false;
 
+	rcu_read_lock();
 	client = get_client_from_socket(socket, state);
 	if (!client) {
 		/* Internal error, abort. */
@@ -3234,12 +3235,13 @@ int handle_notification_thread_client_in(
 		}
 	}
 end:
+	rcu_read_unlock();
 	return ret;
 error_disconnect_client:
 	pthread_mutex_lock(&client->lock);
 	ret = notification_thread_client_disconnect(client, state);
 	pthread_mutex_unlock(&client->lock);
-	return ret;
+	goto end;
 }
 
 /* Client ready to receive outgoing data. */
@@ -3250,6 +3252,7 @@ int handle_notification_thread_client_out(
 	struct notification_client *client;
 	enum client_transmission_status transmission_status;
 
+	rcu_read_lock();
 	client = get_client_from_socket(socket, state);
 	if (!client) {
 		/* Internal error, abort. */
@@ -3266,6 +3269,7 @@ int handle_notification_thread_client_out(
 		goto end;
 	}
 end:
+	rcu_read_unlock();
 	return ret;
 }