Fix: HT must not be destroyed with a rcu_read_lock held

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

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 98e090539af0ecf7755abc2dfe1332b2f116f3fa..c2b0248ea5210e4506b9086d2228b89fbf89c1ff 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -1848,7 +1848,9 @@ int cmd_start_trace(struct ltt_session *session)
         * possible to enable channel thus inform the client.
         */
        if (usess && usess->domain_global.channels) {
+               rcu_read_lock();
                nb_chan += lttng_ht_get_count(usess->domain_global.channels);
+               rcu_read_unlock();
        }
        if (ksession) {
                nb_chan += ksession->channel_count;
@@ -2451,12 +2453,12 @@ ssize_t cmd_list_channels(int domain, struct ltt_session *session,
                                        session->ust_session->domain_global.channels);
                }
                DBG3("Number of UST global channels %zd", nb_chan);
-               if (nb_chan <= 0) {
+               if (nb_chan < 0) {
                        ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+                       goto error;
                }
                break;
        default:
-               *channels = NULL;
                ret = LTTNG_ERR_UND;
                goto error;
        }
@@ -2469,10 +2471,6 @@ ssize_t cmd_list_channels(int domain, struct ltt_session *session,
                }
 
                list_lttng_channels(domain, session, *channels);
-       } else {
-               *channels = NULL;
-               /* Ret value was set in the domain switch case */
-               goto error;
        }
 
        return nb_chan;