Fix: Missing rcu_read_lock in cmd_snapshot_list_outputs()

[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 044e9eefec7e14eab9eb1046411395d1ccdebdff..0a88a26bba7fb04d5a498bbd971840db8ef86988 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -1303,6 +1303,7 @@ error:
 
 /*
  * Command LTTNG_ENABLE_EVENT processed by the client thread.
+ * We own filter, exclusion, and filter_expression.
  */
 int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
@@ -1424,6 +1425,10 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
                /* At this point, the session and channel exist on the tracer */
                ret = event_ust_enable_tracepoint(usess, uchan, event,
                                filter_expression, filter, exclusion);
+               /* We have passed ownership */
+               filter_expression = NULL;
+               filter = NULL;
+               exclusion = NULL;
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -1460,6 +1465,9 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
 
                ret = cmd_enable_event(session, &tmp_dom, DEFAULT_JUL_CHANNEL_NAME,
                        &uevent, filter_expression, filter, NULL, wpipe);
+               /* We have passed ownership */
+               filter_expression = NULL;
+               filter = NULL;
                if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_ENABLED) {
                        goto error;
                }
@@ -1489,6 +1497,9 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
        ret = LTTNG_OK;
 
 error:
+       free(filter_expression);
+       free(filter);
+       free(exclusion);
        rcu_read_unlock();
        return ret;
 }
@@ -1813,7 +1824,9 @@ 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;
@@ -2404,12 +2417,12 @@ 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;
        }
@@ -2422,10 +2435,6 @@ 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;
@@ -2711,7 +2720,7 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
                struct lttng_snapshot_output **outputs)
 {
        int ret, idx = 0;
-       struct lttng_snapshot_output *list;
+       struct lttng_snapshot_output *list = NULL;
        struct lttng_ht_iter iter;
        struct snapshot_output *output;
 
@@ -2725,7 +2734,7 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
         * set in no output mode.
         */
        if (session->output_traces) {
-               ret = LTTNG_ERR_EPERM;
+               ret = -LTTNG_ERR_EPERM;
                goto error;
        }
 
@@ -2736,11 +2745,12 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
 
        list = zmalloc(session->snapshot.nb_output * sizeof(*list));
        if (!list) {
-               ret = LTTNG_ERR_NOMEM;
+               ret = -LTTNG_ERR_NOMEM;
                goto error;
        }
 
        /* Copy list from session to the new list object. */
+       rcu_read_lock();
        cds_lfht_for_each_entry(session->snapshot.output_ht->ht, &iter.iter,
                        output, node.node) {
                assert(output->consumer);
@@ -2755,28 +2765,28 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
                        ret = uri_to_str_url(&output->consumer->dst.net.control,
                                        list[idx].ctrl_url, sizeof(list[idx].ctrl_url));
                        if (ret < 0) {
-                               ret = LTTNG_ERR_NOMEM;
-                               goto free_error;
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto error;
                        }
 
                        /* Data URI. */
                        ret = uri_to_str_url(&output->consumer->dst.net.data,
                                        list[idx].data_url, sizeof(list[idx].data_url));
                        if (ret < 0) {
-                               ret = LTTNG_ERR_NOMEM;
-                               goto free_error;
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto error;
                        }
                }
                idx++;
        }
 
        *outputs = list;
-       return session->snapshot.nb_output;
-
-free_error:
-       free(list);
+       list = NULL;
+       ret = session->snapshot.nb_output;
 error:
-       return -ret;
+       free(list);
+       rcu_read_unlock();
+       return ret;
 }
 
 /*
@@ -2969,12 +2979,14 @@ static uint64_t get_session_max_subbuf_size(struct ltt_session *session)
                struct ltt_ust_channel *uchan;
                struct ltt_ust_session *usess = session->ust_session;
 
+               rcu_read_lock();
                cds_lfht_for_each_entry(usess->domain_global.channels->ht, &iter.iter,
                                uchan, node.node) {
                        if (uchan->attr.subbuf_size > max_size) {
                                max_size = uchan->attr.subbuf_size;
                        }
                }
+               rcu_read_unlock();
        }
 
        return max_size;