Fix: multiple consumer locking problems

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

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 1e9c0be9419f1676735e5b1fe93ec8e3ccc26169..92bf85bc6a615ba5aa3face13efe04a534189bb2 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -448,8 +448,8 @@ static void teardown_ust_session(struct ltt_session *session)
         * lock. This means that there CAN NOT be stream(s) being sent to a
         * consumer since this action also requires the session lock at any time.
         *
-        * At this point, we are sure that not streams data will be lost after this
-        * command is issued.
+        * At this point, we are sure that no data will be lost after this command
+        * is issued.
         */
        if (usess->consumer && usess->consumer->type == CONSUMER_DST_NET) {
                cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter, socket,
@@ -2097,6 +2097,15 @@ static int send_sockets_relayd_consumer(int domain,
 {
        int ret;
 
+       assert(session);
+       assert(consumer);
+
+       /* Don't resend the sockets to the consumer. */
+       if (consumer->dst.net.relayd_socks_sent) {
+               ret = LTTCOMM_OK;
+               goto error;
+       }
+
        /* Sending control relayd socket. */
        ret = send_socket_relayd_consumer(domain, session,
                        &consumer->dst.net.control, consumer, fd);
@@ -2111,6 +2120,9 @@ static int send_sockets_relayd_consumer(int domain,
                goto error;
        }
 
+       /* Flag that all relayd sockets were sent to the consumer. */
+       consumer->dst.net.relayd_socks_sent = 1;
+
 error:
        return ret;
 }
@@ -3647,7 +3659,9 @@ skip_consumer:
 session_error:
        session_destroy(session);
 error:
+       rcu_read_lock();
        consumer_destroy_output(consumer);
+       rcu_read_unlock();
 consumer_error:
        return ret;
 }
@@ -3949,7 +3963,6 @@ static int cmd_set_consumer_uri(int domain, struct ltt_session *session,
        case LTTNG_DOMAIN_KERNEL:
                /* Code flow error if we don't have a kernel session here. */
                assert(ksess);
-               assert(ksess->consumer);
 
                /* Create consumer output if none exists */
                consumer = ksess->tmp_consumer;
@@ -3990,8 +4003,12 @@ static int cmd_set_consumer_uri(int domain, struct ltt_session *session,
                        goto error;
                }
 
-               /* Don't send relayd socket if URI is NOT remote */
-               if (uris[i].dtype == LTTNG_DST_PATH) {
+               /*
+                * Don't send relayd socket if URI is NOT remote or if the relayd
+                * sockets for the session are already sent.
+                */
+               if (uris[i].dtype == LTTNG_DST_PATH ||
+                               consumer->dst.net.relayd_socks_sent) {
                        continue;
                }
 
@@ -4180,7 +4197,9 @@ static int cmd_enable_consumer(int domain, struct ltt_session *session)
                 * session without this lock hence freeing the consumer output object
                 * is valid.
                 */
+               rcu_read_lock();
                consumer_destroy_output(ksess->consumer);
+               rcu_read_unlock();
                ksess->consumer = consumer;
                ksess->tmp_consumer = NULL;
 
@@ -4263,7 +4282,9 @@ static int cmd_enable_consumer(int domain, struct ltt_session *session)
                 * session without this lock hence freeing the consumer output object
                 * is valid.
                 */
+               rcu_read_lock();
                consumer_destroy_output(usess->consumer);
+               rcu_read_unlock();
                usess->consumer = consumer;
                usess->tmp_consumer = NULL;