Fix: unchecked return value in ust app delete
[lttng-tools.git] / src / bin / lttng-sessiond / ust-app.c
index 47cd71f9dbefd1eb9f8450592b453b0225ff07d3..9a8a11acab6292c36c6a2350af7c4be2e22c1c10 100644 (file)
@@ -389,7 +389,8 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan,
        if (ua_chan->obj != NULL) {
                /* Remove channel from application UST object descriptor. */
                iter.iter.node = &ua_chan->ust_objd_node.node;
-               lttng_ht_del(app->ust_objd, &iter);
+               ret = lttng_ht_del(app->ust_objd, &iter);
+               assert(!ret);
                ret = ustctl_release_object(sock, ua_chan->obj);
                if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
                        ERR("UST app sock %d release channel obj failed with ret %d",
@@ -464,6 +465,25 @@ push_data:
        ret = consumer_push_metadata(socket, registry->metadata_key,
                        metadata_str, len, offset);
        if (ret < 0) {
+               /*
+                * There is an acceptable race here between the registry metadata key
+                * assignment and the creation on the consumer. The session daemon can
+                * concurrently push metadata for this registry while being created on
+                * the consumer since the metadata key of the registry is assigned
+                * *before* it is setup to avoid the consumer to ask for metadata that
+                * could possibly be not found in the session daemon.
+                *
+                * The metadata will get pushed either by the session being stopped or
+                * the consumer requesting metadata if that race is triggered.
+                */
+               if (ret == -LTTCOMM_CONSUMERD_CHANNEL_FAIL) {
+                       ret = 0;
+               }
+
+               /* Update back the actual metadata len sent since it failed here. */
+               pthread_mutex_lock(&registry->lock);
+               registry->metadata_len_sent -= len;
+               pthread_mutex_unlock(&registry->lock);
                ret_val = ret;
                goto error_push;
        }
@@ -1055,6 +1075,12 @@ int create_ust_channel_context(struct ust_app_channel *ua_chan,
                        ERR("UST app create channel context failed for app (pid: %d) "
                                        "with ret %d", app->pid, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app disable event failed. Application is dead.");
                }
                goto error;
@@ -1093,6 +1119,12 @@ int set_ust_event_filter(struct ust_app_event *ua_event,
                        ERR("UST app event %s filter failed for app (pid: %d) "
                                        "with ret %d", ua_event->attr.name, app->pid, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app filter event failed. Application is dead.");
                }
                goto error;
@@ -1122,6 +1154,12 @@ static int disable_ust_event(struct ust_app *app,
                                        "and session handle %d with ret %d",
                                        ua_event->attr.name, app->pid, ua_sess->handle, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app disable event failed. Application is dead.");
                }
                goto error;
@@ -1152,6 +1190,12 @@ static int disable_ust_channel(struct ust_app *app,
                                        "and session handle %d with ret %d",
                                        ua_chan->name, app->pid, ua_sess->handle, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app disable channel failed. Application is dead.");
                }
                goto error;
@@ -1182,6 +1226,12 @@ static int enable_ust_channel(struct ust_app *app,
                                        "and session handle %d with ret %d",
                                        ua_chan->name, app->pid, ua_sess->handle, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app enable channel failed. Application is dead.");
                }
                goto error;
@@ -1214,6 +1264,12 @@ static int enable_ust_event(struct ust_app *app,
                                        "and session handle %d with ret %d",
                                        ua_event->attr.name, app->pid, ua_sess->handle, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app enable event failed. Application is dead.");
                }
                goto error;
@@ -1294,6 +1350,12 @@ int create_ust_event(struct ust_app *app, struct ust_app_session *ua_sess,
                        ERR("Error ustctl create event %s for app pid: %d with ret %d",
                                        ua_event->attr.name, app->pid, ret);
                } else {
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       ret = 0;
                        DBG3("UST app create event failed. Application is dead.");
                }
                goto error;
@@ -1731,6 +1793,13 @@ static int create_ust_app_session(struct ltt_ust_session *usess,
                                                app->pid, ret);
                        } else {
                                DBG("UST app creating session failed. Application is dead");
+                               /*
+                                * This is normal behavior, an application can die during the
+                                * creation process. Don't report an error so the execution can
+                                * continue normally. This will get flagged ENOTCONN and the
+                                * caller will handle it.
+                                */
+                               ret = 0;
                        }
                        delete_ust_app_session(-1, ua_sess, app);
                        if (ret != -ENOMEM) {
@@ -2998,6 +3067,12 @@ int ust_app_list_events(struct lttng_event **events)
                                                        app->sock, ret);
                                } else {
                                        DBG3("UST app tp list get failed. Application is dead");
+                                       /*
+                                        * This is normal behavior, an application can die during the
+                                        * creation process. Don't report an error so the execution can
+                                        * continue normally. Continue normal execution.
+                                        */
+                                       break;
                                }
                                goto rcu_error;
                        }
@@ -3092,6 +3167,12 @@ int ust_app_list_event_fields(struct lttng_event_field **fields)
                                                        app->sock, ret);
                                } else {
                                        DBG3("UST app tp list field failed. Application is dead");
+                                       /*
+                                        * This is normal behavior, an application can die during the
+                                        * creation process. Don't report an error so the execution can
+                                        * continue normally.
+                                        */
+                                       break;
                                }
                                goto rcu_error;
                        }
@@ -3115,12 +3196,13 @@ int ust_app_list_event_fields(struct lttng_event_field **fields)
                        }
 
                        memcpy(tmp_event[count].field_name, uiter.field_name, LTTNG_UST_SYM_NAME_LEN);
-                       tmp_event[count].type = uiter.type;
+                       /* Mapping between these enums matches 1 to 1. */
+                       tmp_event[count].type = (enum lttng_event_field_type) uiter.type;
                        tmp_event[count].nowrite = uiter.nowrite;
 
                        memcpy(tmp_event[count].event.name, uiter.event_name, LTTNG_UST_SYM_NAME_LEN);
                        tmp_event[count].event.loglevel = uiter.loglevel;
-                       tmp_event[count].event.type = LTTNG_UST_TRACEPOINT;
+                       tmp_event[count].event.type = LTTNG_EVENT_TRACEPOINT;
                        tmp_event[count].event.pid = app->pid;
                        tmp_event[count].event.enabled = -1;
                        count++;
@@ -3707,6 +3789,13 @@ skip_setup:
                                        app->pid, ret);
                } else {
                        DBG("UST app start session failed. Application is dead.");
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       pthread_mutex_unlock(&ua_sess->lock);
+                       goto end;
                }
                goto error_unlock;
        }
@@ -3782,6 +3871,12 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
                                        app->pid, ret);
                } else {
                        DBG("UST app stop session failed. Application is dead.");
+                       /*
+                        * This is normal behavior, an application can die during the
+                        * creation process. Don't report an error so the execution can
+                        * continue normally.
+                        */
+                       goto end_unlock;
                }
                goto error_rcu_unlock;
        }
@@ -3805,6 +3900,7 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
                (void) push_metadata(registry, ua_sess->consumer);
        }
 
+end_unlock:
        pthread_mutex_unlock(&ua_sess->lock);
 end_no_session:
        rcu_read_unlock();
@@ -3859,8 +3955,11 @@ int ust_app_flush_trace(struct ltt_ust_session *usess, struct ust_app *app)
                        } else {
                                DBG3("UST app failed to flush %s. Application is dead.",
                                                ua_chan->name);
-                               /* No need to continue. */
-                               break;
+                               /*
+                                * This is normal behavior, an application can die during the
+                                * creation process. Don't report an error so the execution can
+                                * continue normally.
+                                */
                        }
                        /* Continuing flushing all buffers */
                        continue;
@@ -4662,7 +4761,8 @@ static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name,
         */
        ret_code = ust_registry_create_event(registry, chan_reg_key,
                        sobjd, cobjd, name, sig, nr_fields, fields, loglevel,
-                       model_emf_uri, ua_sess->buffer_type, &event_id);
+                       model_emf_uri, ua_sess->buffer_type, &event_id,
+                       app);
 
        /*
         * The return value is returned to ustctl so in case of an error, the
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