Fix: notifier: use store-release/load-acquire for error counter

[lttng-modules.git] / src / lttng-event-notifier-notification.c

diff --git a/src/lttng-event-notifier-notification.c b/src/lttng-event-notifier-notification.c
index f681d9b79d24486ca03fa911967f6cc5fe7e3200..77e72842d410782e89aaa21bdb9f1e835e0ad936 100644 (file)
--- a/src/lttng-event-notifier-notification.c
+++ b/src/lttng-event-notifier-notification.c
@@ -352,17 +352,23 @@ void record_error(struct lttng_event_notifier *event_notifier)
 {
 
        struct lttng_event_notifier_group *event_notifier_group = event_notifier->group;
+       struct lttng_counter *error_counter;
        size_t dimension_index[1];
        int ret;
 
+       /*
+        * smp_load_acquire paired with smp_store_release orders
+        * creation of the error counter and setting error_counter_len
+        * before the error_counter is used.
+        */
+       error_counter = smp_load_acquire(&event_notifier_group->error_counter);
        /* This group may not have an error counter attached to it. */
-       if (!event_notifier_group->error_counter)
+       if (!error_counter)
                return;
 
        dimension_index[0] = event_notifier->error_counter_index;
 
-       ret = event_notifier_group->error_counter->ops->counter_add(
-                       event_notifier_group->error_counter->counter,
+       ret = error_counter->ops->counter_add(error_counter->counter,
                        dimension_index, 1);
        if (ret)
                WARN_ON_ONCE(1);