+static
+struct lttng_kernel_event_notifier *_lttng_kernel_event_notifier_create(struct lttng_event_notifier_enabler *event_enabler,
+ const struct lttng_kernel_event_desc *event_desc)
+{
+ struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(&event_enabler->parent);
+ struct lttng_event_notifier_group *event_notifier_group = event_enabler->group;
+ struct lttng_kernel_abi_event *event_param = &event_enabler->parent.event_param;
+ uint64_t token = event_enabler->parent.user_token;
+ enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+ struct lttng_kernel_event_notifier *event_notifier;
+ struct lttng_kernel_event_notifier_private *event_notifier_priv;
+ struct lttng_kernel_event_common_private *event_priv;
+ struct lttng_counter *error_counter;
+ const char *event_name;
+ struct hlist_head *head;
+ int ret;
+
+ switch (itype) {
+ case LTTNG_KERNEL_ABI_TRACEPOINT:
+ event_name = event_desc->event_name;
+ break;
+
+ case LTTNG_KERNEL_ABI_KPROBE:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_UPROBE:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_SYSCALL:
+ event_name = event_param->name;
+ break;
+
+ case LTTNG_KERNEL_ABI_KRETPROBE:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_FUNCTION:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_NOOP:
+ lttng_fallthrough;
+ default:
+ WARN_ON_ONCE(1);
+ ret = -EINVAL;
+ goto type_error;
+ }
+
+ head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, event_name);
+ lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
+ event_notifier_priv = container_of(event_priv, struct lttng_kernel_event_notifier_private, parent);
+
+ WARN_ON_ONCE(!event_priv->desc);
+ if (!strncmp(event_priv->desc->event_name, event_name,
+ LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1)
+ && event_notifier_group == event_notifier_priv->group
+ && token == event_priv->user_token) {
+ ret = -EEXIST;
+ goto exist;
+ }
+ }
+
+ event_notifier = kmem_cache_zalloc(event_notifier_cache, GFP_KERNEL);
+ if (!event_notifier) {
+ ret = -ENOMEM;
+ goto cache_error;
+ }
+ event_notifier_priv = kmem_cache_zalloc(event_notifier_private_cache, GFP_KERNEL);
+ if (!event_notifier_priv) {
+ ret = -ENOMEM;
+ goto cache_private_error;
+ }
+ event_notifier_priv->pub = event_notifier;
+ event_notifier_priv->parent.pub = &event_notifier->parent;
+ event_notifier->priv = event_notifier_priv;
+ event_notifier->parent.priv = &event_notifier_priv->parent;
+ event_notifier->parent.type = LTTNG_KERNEL_EVENT_TYPE_NOTIFIER;
+
+ event_notifier->priv->group = event_notifier_group;
+ event_notifier->priv->parent.user_token = event_enabler->parent.user_token;
+ event_notifier->priv->error_counter_index = event_enabler->error_counter_index;
+ event_notifier->priv->num_captures = 0;
+ event_notifier->priv->parent.instrumentation = itype;
+ event_notifier->notification_send = lttng_event_notifier_notification_send;
+ INIT_LIST_HEAD(&event_notifier->priv->parent.filter_bytecode_runtime_head);
+ INIT_LIST_HEAD(&event_notifier->priv->parent.enablers_ref_head);
+ INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
+ event_notifier->parent.run_filter = lttng_kernel_interpret_event_filter;
+
+ switch (itype) {
+ case LTTNG_KERNEL_ABI_TRACEPOINT:
+ /* Event will be enabled by enabler sync. */
+ event_notifier->parent.enabled = 0;
+ event_notifier->priv->parent.registered = 0;
+ event_notifier->priv->parent.desc = lttng_event_desc_get(event_name);
+ if (!event_notifier->priv->parent.desc) {
+ ret = -ENOENT;
+ goto register_error;
+ }
+ /* Populate lttng_event_notifier structure before event registration. */
+ smp_wmb();
+ break;
+
+ case LTTNG_KERNEL_ABI_KPROBE:
+ /*
+ * Needs to be explicitly enabled after creation, since
+ * we may want to apply filters.
+ */
+ event_notifier->parent.enabled = 0;
+ event_notifier->priv->parent.registered = 1;
+ /*
+ * Populate lttng_event_notifier structure before event
+ * registration.
+ */
+ smp_wmb();
+ ret = lttng_kprobes_register_event(event_param->u.kprobe.symbol_name,
+ event_param->u.kprobe.symbol_name,
+ event_param->u.kprobe.offset,
+ event_param->u.kprobe.addr,
+ &event_notifier->parent);
+ if (ret) {
+ ret = -EINVAL;
+ goto register_error;
+ }
+ ret = try_module_get(event_notifier->priv->parent.desc->owner);
+ WARN_ON_ONCE(!ret);
+ break;
+
+ case LTTNG_KERNEL_ABI_SYSCALL:
+ /*
+ * Needs to be explicitly enabled after creation, since
+ * we may want to apply filters.
+ */
+ event_notifier->parent.enabled = 0;
+ event_notifier->priv->parent.registered = 0;
+ event_notifier->priv->parent.desc = event_desc;
+ switch (event_param->u.syscall.entryexit) {
+ case LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT:
+ ret = -EINVAL;
+ goto register_error;
+ case LTTNG_KERNEL_ABI_SYSCALL_ENTRY:
+ event_notifier->priv->parent.u.syscall.entryexit = LTTNG_SYSCALL_ENTRY;
+ break;
+ case LTTNG_KERNEL_ABI_SYSCALL_EXIT:
+ event_notifier->priv->parent.u.syscall.entryexit = LTTNG_SYSCALL_EXIT;
+ break;
+ }
+ switch (event_param->u.syscall.abi) {
+ case LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL:
+ ret = -EINVAL;
+ goto register_error;
+ case LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE:
+ event_notifier->priv->parent.u.syscall.abi = LTTNG_SYSCALL_ABI_NATIVE;
+ break;
+ case LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT:
+ event_notifier->priv->parent.u.syscall.abi = LTTNG_SYSCALL_ABI_COMPAT;
+ break;
+ }
+
+ if (!event_notifier->priv->parent.desc) {
+ ret = -EINVAL;
+ goto register_error;
+ }
+ break;
+
+ case LTTNG_KERNEL_ABI_UPROBE:
+ /*
+ * Needs to be explicitly enabled after creation, since
+ * we may want to apply filters.
+ */
+ event_notifier->parent.enabled = 0;
+ event_notifier->priv->parent.registered = 1;
+
+ /*
+ * Populate lttng_event_notifier structure before
+ * event_notifier registration.
+ */
+ smp_wmb();
+
+ ret = lttng_uprobes_register_event(event_param->name,
+ event_param->u.uprobe.fd,
+ &event_notifier->parent);
+ if (ret)
+ goto register_error;
+ ret = try_module_get(event_notifier->priv->parent.desc->owner);
+ WARN_ON_ONCE(!ret);
+ break;
+
+ case LTTNG_KERNEL_ABI_KRETPROBE:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_FUNCTION:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_NOOP:
+ lttng_fallthrough;
+ default:
+ WARN_ON_ONCE(1);
+ ret = -EINVAL;
+ goto register_error;
+ }
+
+ list_add(&event_notifier->priv->parent.node, &event_notifier_group->event_notifiers_head);
+ hlist_add_head(&event_notifier->priv->parent.hlist_node, head);
+
+ /*
+ * Clear the error counter bucket. The sessiond keeps track of which
+ * bucket is currently in use. We trust it. The session lock
+ * synchronizes against concurrent creation of the error
+ * counter.
+ */
+ error_counter = event_notifier_group->error_counter;
+ if (error_counter) {
+ size_t dimension_index[1];
+
+ /*
+ * Check that the index is within the boundary of the counter.
+ */
+ if (event_notifier->priv->error_counter_index >= event_notifier_group->error_counter_len) {
+ printk(KERN_INFO "LTTng: event_notifier: Error counter index out-of-bound: counter-len=%zu, index=%llu\n",
+ event_notifier_group->error_counter_len, event_notifier->priv->error_counter_index);
+ ret = -EINVAL;
+ goto register_error;
+ }
+
+ dimension_index[0] = event_notifier->priv->error_counter_index;
+ ret = error_counter->ops->counter_clear(error_counter->counter, dimension_index);
+ if (ret) {
+ printk(KERN_INFO "LTTng: event_notifier: Unable to clear error counter bucket %llu\n",
+ event_notifier->priv->error_counter_index);
+ goto register_error;
+ }
+ }
+
+ return event_notifier;
+
+register_error:
+ kmem_cache_free(event_notifier_private_cache, event_notifier_priv);
+cache_private_error:
+ kmem_cache_free(event_notifier_cache, event_notifier);
+cache_error:
+exist:
+type_error:
+ return ERR_PTR(ret);
+}
+
+struct lttng_kernel_event_common *_lttng_kernel_event_create(struct lttng_event_enabler_common *event_enabler,
+ const struct lttng_kernel_event_desc *event_desc)
+{
+ switch (event_enabler->enabler_type) {
+ case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+ {
+ struct lttng_event_recorder_enabler *event_recorder_enabler =
+ container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+ struct lttng_kernel_event_recorder *event_recorder;
+
+ event_recorder = _lttng_kernel_event_recorder_create(event_recorder_enabler, event_desc);
+ if (!event_recorder)
+ return NULL;
+ return &event_recorder->parent;
+ }
+ case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+ {
+ struct lttng_event_notifier_enabler *event_notifier_enabler =
+ container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+ struct lttng_kernel_event_notifier *event_notifier;
+
+ event_notifier = _lttng_kernel_event_notifier_create(event_notifier_enabler, event_desc);
+ if (!event_notifier)
+ return NULL;
+ return &event_notifier->parent;
+ }
+ default:
+ return NULL;
+ }
+}
+
+struct lttng_kernel_event_common *lttng_kernel_event_create(struct lttng_event_enabler_common *event_enabler,
+ const struct lttng_kernel_event_desc *event_desc)