X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;fp=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=2dc13da09ca5f125b0b71d17b48a3995d5ce7269;hp=4d3a08508c8f2a3e0b28ee00f6c895859833aa8b;hb=be355079dc40848a2b654b1f0871dfa99a4876de;hpb=3a2434036c2e836d58bfa5b89ba47b5898d86d35

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 4d3a08508..2dc13da09 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -292,9 +292,18 @@ void delete_ust_app_ctx(int sock, struct ust_app_ctx *ua_ctx,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_object(sock, ua_ctx->obj);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app sock %d release ctx obj handle %d failed with ret %d",
-					sock, ua_ctx->obj->handle, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app release ctx failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app release ctx failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("UST app release ctx obj handle %d failed with ret %d: pid = %d, sock = %d",
+						ua_ctx->obj->handle, ret,
+						app->pid, app->sock);
+			}
 		}
 		free(ua_ctx->obj);
 	}
@@ -320,9 +329,17 @@ void delete_ust_app_event(int sock, struct ust_app_event *ua_event,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_object(sock, ua_event->obj);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app sock %d release event obj failed with ret %d",
-					sock, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app release event failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app release event failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("UST app release event obj failed with ret %d: pid = %d, sock = %d",
+						ret, app->pid, app->sock);
+			}
 		}
 		free(ua_event->obj);
 	}
@@ -361,9 +378,17 @@ static void delete_ust_app_event_notifier_rule(int sock,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_object(sock, ua_event_notifier_rule->obj);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Failed to release event notifier object: app = '%s' (ppid %d), ret = %d",
-					app->name, (int) app->ppid, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app release event notifier failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app release event notifier failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("UST app release event notifier failed with ret %d: pid = %d, sock = %d",
+						ret, app->pid, app->sock);
+			}
 		}
 
 		free(ua_event_notifier_rule->obj);
@@ -390,9 +415,17 @@ static int release_ust_app_stream(int sock, struct ust_app_stream *stream,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_object(sock, stream->obj);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app sock %d release stream obj failed with ret %d",
-					sock, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app release stream failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app release stream failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("UST app release stream obj failed with ret %d: pid = %d, sock = %d",
+						ret, app->pid, app->sock);
+			}
 		}
 		lttng_fd_put(LTTNG_FD_APPS, 2);
 		free(stream->obj);
@@ -566,9 +599,20 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_object(sock, ua_chan->obj);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app sock %d release channel obj failed with ret %d",
-					sock, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app channel %s release failed. Application is dead: pid = %d, sock = %d",
+						ua_chan->name, app->pid,
+						app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app channel %s release failed. Communication time out: pid = %d, sock = %d",
+						ua_chan->name, app->pid,
+						app->sock);
+			} else {
+				ERR("UST app channel %s release failed with ret %d: pid = %d, sock = %d",
+						ua_chan->name, ret, app->pid,
+						app->sock);
+			}
 		}
 		lttng_fd_put(LTTNG_FD_APPS, 1);
 		free(ua_chan->obj);
@@ -931,10 +975,19 @@ void delete_ust_app_session(int sock, struct ust_app_session *ua_sess,
 		pthread_mutex_lock(&app->sock_lock);
 		ret = lttng_ust_ctl_release_handle(sock, ua_sess->handle);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app sock %d release session handle failed with ret %d",
-					sock, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app release session handle failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app release session handle failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("UST app release session handle failed with ret %d: pid = %d, sock = %d",
+						ret, app->pid, app->sock);
+			}
 		}
+
 		/* Remove session from application UST object descriptor. */
 		iter.iter.node = &ua_sess->ust_objd_node.node;
 		ret = lttng_ht_del(app->ust_sessions_objd, &iter);
@@ -1526,17 +1579,17 @@ int create_ust_channel_context(struct ust_app_channel *ua_chan,
 			ua_chan->obj, &ua_ctx->obj);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 			ret = 0;
-			DBG3("UST app add context failed. Application is dead.");
+			DBG3("UST app create channel context failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			WARN("UST app create channel context failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app create channel context failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		goto error;
 	}
@@ -1573,17 +1626,17 @@ static int set_ust_object_filter(struct ust_app *app,
 			ust_object);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app set object filter failed: object = %p of app pid = %d, ret = %d",
-					ust_object, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app  set filter failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
 			ret = 0;
-			DBG3("Failed to set UST app object filter. Application is dead.");
+			WARN("UST app  set filter failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app  set filter failed with ret %d: pid = %d, sock = %d, object = %p",
+					ret, app->pid, app->sock, ust_object);
 		}
 		goto error;
 	}
@@ -1627,17 +1680,18 @@ static int set_ust_capture(struct ust_app *app,
 			ust_object);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app set object capture failed: object = %p of app pid = %d, ret = %d",
-					ust_object, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 			ret = 0;
-			DBG3("Failed to set UST app object capture. Application is dead.");
+			DBG3("UST app set capture failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			DBG3("UST app set capture failed. Communication timeout: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app event set capture failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid,
+					app->sock);
 		}
 
 		goto error;
@@ -1696,17 +1750,17 @@ static int set_ust_object_exclusions(struct ust_app *app,
 	ret = lttng_ust_ctl_set_exclusion(app->sock, ust_exclusions, ust_object);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Failed to set UST app exclusions for object %p of app (pid: %d) "
-					"with ret %d", ust_object, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 			ret = 0;
-			DBG3("Failed to set UST app object exclusions. Application is dead.");
+			DBG3("UST app event exclusion failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			WARN("UST app event exclusion failed. Communication time out(pid: %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app event exclusions failed with ret %d: pid = %d, sock = %d, object = %p",
+					ret, app->pid, app->sock, ust_object);
 		}
 		goto error;
 	}
@@ -1733,22 +1787,22 @@ static int disable_ust_object(struct ust_app *app,
 	ret = lttng_ust_ctl_disable(app->sock, object);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Failed to disable UST app object %p app (pid: %d) with ret %d",
-					object, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app disable object failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
 			ret = 0;
-			DBG3("Failed to disable UST app object. Application is dead.");
+			WARN("UST app disable object failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app disable object failed with ret %d: pid = %d, sock = %d, object = %p",
+					ret, app->pid, app->sock, object);
 		}
 		goto error;
 	}
 
-	DBG2("UST app object %p disabled successfully for app (pid: %d)",
+	DBG2("UST app object %p disabled successfully for app: pid = %d",
 			object, app->pid);
 
 error:
@@ -1770,23 +1824,23 @@ static int disable_ust_channel(struct ust_app *app,
 	ret = lttng_ust_ctl_disable(app->sock, ua_chan->obj);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app channel %s disable failed for app (pid: %d) "
-					"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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 			ret = 0;
-			DBG3("UST app disable channel failed. Application is dead.");
+			DBG3("UST app disable channel failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			WARN("UST app disable channel failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app channel %s disable failed, session handle %d, with ret %d: pid = %d, sock = %d",
+					ua_chan->name, ua_sess->handle, ret,
+					app->pid, app->sock);
 		}
 		goto error;
 	}
 
-	DBG2("UST app channel %s disabled successfully for app (pid: %d)",
+	DBG2("UST app channel %s disabled successfully for app: pid = %d",
 			ua_chan->name, app->pid);
 
 error:
@@ -1808,25 +1862,25 @@ static int enable_ust_channel(struct ust_app *app,
 	ret = lttng_ust_ctl_enable(app->sock, ua_chan->obj);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app channel %s enable failed for app (pid: %d) "
-					"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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app channel %s enable failed. Application is dead: pid = %d, sock = %d",
+					ua_chan->name, app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
 			ret = 0;
-			DBG3("UST app enable channel failed. Application is dead.");
+			WARN("UST app channel %s enable failed. Communication time out: pid = %d, sock = %d",
+					ua_chan->name, app->pid, app->sock);
+		} else {
+			ERR("UST app channel %s enable failed, session handle %d, with ret %d: pid = %d, sock = %d",
+					ua_chan->name, ua_sess->handle, ret,
+					app->pid, app->sock);
 		}
 		goto error;
 	}
 
 	ua_chan->enabled = 1;
 
-	DBG2("UST app channel %s enabled successfully for app (pid: %d)",
+	DBG2("UST app channel %s enabled successfully for app: pid = %d",
 			ua_chan->name, app->pid);
 
 error:
@@ -1848,22 +1902,22 @@ static int enable_ust_object(
 	ret = lttng_ust_ctl_enable(app->sock, ust_object);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app enable failed for object %p app (pid: %d) with ret %d",
-					ust_object, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 			ret = 0;
-			DBG3("Failed to enable UST app object. Application is dead.");
+			DBG3("UST app enable object failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			WARN("UST app enable object failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app enable object failed with ret %d: pid = %d, sock = %d, object = %p",
+					ret, app->pid, app->sock, ust_object);
 		}
 		goto error;
 	}
 
-	DBG2("UST app object %p enabled successfully for app (pid: %d)",
+	DBG2("UST app object %p enabled successfully for app: pid = %d",
 			ust_object, app->pid);
 
 error:
@@ -1896,6 +1950,13 @@ static int send_channel_pid_to_ust(struct ust_app *app,
 	if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 		ret = -ENOTCONN;	/* Caused by app exiting. */
 		goto error;
+	} else if (ret == -EAGAIN) {
+		/* Caused by timeout. */
+		WARN("Communication with application %d timed out on send_channel for channel \"%s\" of session \"%" PRIu64 "\".",
+				app->pid, ua_chan->name, ua_sess->tracing_id);
+		/* Treat this the same way as an application that is exiting. */
+		ret = -ENOTCONN;
+		goto error;
 	} else if (ret < 0) {
 		goto error;
 	}
@@ -1906,8 +1967,16 @@ static int send_channel_pid_to_ust(struct ust_app *app,
 	cds_list_for_each_entry_safe(stream, stmp, &ua_chan->streams.head, list) {
 		ret = ust_consumer_send_stream_to_ust(app, ua_chan, stream);
 		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
-			ret = -ENOTCONN;	/* Caused by app exiting. */
+			ret = -ENOTCONN; /* Caused by app exiting. */
 			goto error;
+		} else if (ret == -EAGAIN) {
+			/* Caused by timeout. */
+			WARN("Communication with application %d timed out on send_stream for stream \"%s\" of channel \"%s\" of session \"%" PRIu64 "\".",
+					app->pid, stream->name, ua_chan->name,
+					ua_sess->tracing_id);
+			/* Treat this the same way as an application that is
+			 * exiting. */
+			ret = -ENOTCONN;
 		} else if (ret < 0) {
 			goto error;
 		}
@@ -1942,25 +2011,25 @@ int create_ust_event(struct ust_app *app, struct ust_app_session *ua_sess,
 			&ua_event->obj);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			abort();
-			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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app create event failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
 			ret = 0;
-			DBG3("UST app create event failed. Application is dead.");
+			WARN("UST app create event failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app create event '%s' failed with ret %d: pid = %d, sock = %d",
+					ua_event->attr.name, ret, app->pid,
+					app->sock);
 		}
 		goto error;
 	}
 
 	ua_event->handle = ua_event->obj->handle;
 
-	DBG2("UST app event %s created successfully for pid:%d object: %p",
+	DBG2("UST app event %s created successfully for pid:%d object = %p",
 			ua_event->attr.name, app->pid, ua_event->obj);
 
 	health_code_update();
@@ -2143,28 +2212,26 @@ static int create_ust_event_notifier(struct ust_app *app,
 			&ua_event_notifier_rule->obj);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Error ustctl create event notifier: name = '%s', app = '%s' (ppid: %d), ret = %d",
-					event_notifier.event.name, app->name,
-					app->ppid, 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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app create event notifier failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
 			ret = 0;
-			DBG3("UST app create event notifier failed (application is dead): app = '%s' (ppid = %d)",
-					app->name, app->ppid);
+			WARN("UST app create event notifier failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app create event notifier '%s' failed with ret %d: pid = %d, sock = %d",
+					event_notifier.event.name, ret, app->pid,
+					app->sock);
 		}
-
 		goto error;
 	}
 
 	ua_event_notifier_rule->handle = ua_event_notifier_rule->obj->handle;
 
-	DBG2("UST app event notifier %s created successfully: app = '%s' (ppid: %d), object: %p",
-			event_notifier.event.name, app->name, app->ppid,
+	DBG2("UST app event notifier %s created successfully: app = '%s': pid = %d), object = %p",
+			event_notifier.event.name, app->name, app->pid,
 			ua_event_notifier_rule->obj);
 
 	health_code_update();
@@ -2640,18 +2707,17 @@ static int find_or_create_ust_app_session(struct ltt_ust_session *usess,
 		ret = lttng_ust_ctl_create_session(app->sock);
 		pthread_mutex_unlock(&app->sock_lock);
 		if (ret < 0) {
-			if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-				ERR("Creating session for app pid %d with ret %d",
-						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.
-				 */
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG("UST app creating session failed. Application is dead: pid = %d, sock = %d",
+						app->pid, app->sock);
 				ret = 0;
+			} else if (ret == -EAGAIN) {
+				DBG("UST app creating session failed. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+				ret = 0;
+			} else {
+				ERR("UST app creating session failed with ret %d: pid = %d, sock =%d",
+						ret, app->pid, app->sock);
 			}
 			delete_ust_app_session(-1, ua_sess, app);
 			if (ret != -ENOMEM) {
@@ -3233,6 +3299,13 @@ static int send_channel_uid_to_ust(struct buffer_reg_channel *buf_reg_chan,
 	if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 		ret = -ENOTCONN;	/* Caused by app exiting. */
 		goto error;
+	} else if (ret == -EAGAIN) {
+		/* Caused by timeout. */
+		WARN("Communication with application %d timed out on send_channel for channel \"%s\" of session \"%" PRIu64 "\".",
+				app->pid, ua_chan->name, ua_sess->tracing_id);
+		/* Treat this the same way as an application that is exiting. */
+		ret = -ENOTCONN;
+		goto error;
 	} else if (ret < 0) {
 		goto error;
 	}
@@ -3251,10 +3324,21 @@ static int send_channel_uid_to_ust(struct buffer_reg_channel *buf_reg_chan,
 
 		ret = ust_consumer_send_stream_to_ust(app, ua_chan, &stream);
 		if (ret < 0) {
-			(void) release_ust_app_stream(-1, &stream, app);
 			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 				ret = -ENOTCONN; /* Caused by app exiting. */
+			} else if (ret == -EAGAIN) {
+				/*
+				 * Caused by timeout.
+				 * Treat this the same way as an application
+				 * that is exiting.
+				 */
+				WARN("Communication with application %d timed out on send_stream for stream \"%s\" of channel \"%s\" of session \"%" PRIu64 "\".",
+						app->pid, stream.name,
+						ua_chan->name,
+						ua_sess->tracing_id);
+				ret = -ENOTCONN;
 			}
+			(void) release_ust_app_stream(-1, &stream, app);
 			goto error_stream_unlock;
 		}
 
@@ -3649,8 +3733,8 @@ int create_ust_app_event(struct ust_app_session *ua_sess,
 
 	add_unique_ust_app_event(ua_chan, ua_event);
 
-	DBG2("UST app create event completed: app = '%s' (ppid: %d)",
-			app->name, app->ppid);
+	DBG2("UST app create event completed: app = '%s' pid = %d",
+			app->name, app->pid);
 
 end:
 	return ret;
@@ -3702,8 +3786,8 @@ int create_ust_app_event_notifier_rule(struct lttng_trigger *trigger,
 	lttng_ht_add_unique_u64(app->token_to_event_notifier_rule_ht,
 			&ua_event_notifier_rule->node);
 
-	DBG2("UST app create token event rule completed: app = '%s' (ppid: %d), token = %" PRIu64,
-			app->name, app->ppid, lttng_trigger_get_tracer_token(trigger));
+	DBG2("UST app create token event rule completed: app = '%s', pid = %d), token = %" PRIu64,
+			app->name, app->pid, lttng_trigger_get_tracer_token(trigger));
 
 	goto end;
 
@@ -3885,15 +3969,15 @@ struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
 	 */
 	ret = lttng_fd_get(LTTNG_FD_APPS, 2);
 	if (ret) {
-		ERR("Failed to reserve two file descriptors for the event source pipe while creating a new application instance: app = '%s' (ppid: %d)",
-				msg->name, (int) msg->ppid);
+		ERR("Failed to reserve two file descriptors for the event source pipe while creating a new application instance: app = '%s', pid = %d",
+				msg->name, (int) msg->pid);
 		goto error;
 	}
 
 	event_notifier_event_source_pipe = lttng_pipe_open(FD_CLOEXEC);
 	if (!event_notifier_event_source_pipe) {
-		PERROR("Failed to open application event source pipe: '%s' (ppid = %d)",
-				msg->name, msg->ppid);
+		PERROR("Failed to open application event source pipe: '%s' (pid = %d)",
+				msg->name, msg->pid);
 		goto error;
 	}
 
@@ -3981,8 +4065,8 @@ void ust_app_add(struct ust_app *app)
 	lttng_ht_node_init_ulong(&app->notify_sock_n, app->notify_sock);
 	lttng_ht_add_unique_ulong(ust_app_ht_by_notify_sock, &app->notify_sock_n);
 
-	DBG("App registered with pid:%d ppid:%d uid:%d gid:%d sock:%d name:%s "
-			"notify_sock:%d (version %d.%d)", app->pid, app->ppid, app->uid,
+	DBG("App registered with pid:%d ppid:%d uid:%d gid:%d sock =%d name:%s "
+			"notify_sock =%d (version %d.%d)", app->pid, app->ppid, app->uid,
 			app->gid, app->sock, app->name, app->notify_sock, app->v_major,
 			app->v_minor);
 
@@ -4005,10 +4089,15 @@ int ust_app_version(struct ust_app *app)
 	ret = lttng_ust_ctl_tracer_version(app->sock, &app->version);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -LTTNG_UST_ERR_EXITING && ret != -EPIPE) {
-			ERR("UST app %d version failed with ret %d", app->sock, ret);
+		if (ret == -LTTNG_UST_ERR_EXITING || ret == -EPIPE) {
+			DBG3("UST app version failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app version failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
 		} else {
-			DBG3("UST app %d version failed. Application is dead", app->sock);
+			ERR("UST app version failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 	}
 
@@ -4055,21 +4144,25 @@ int ust_app_setup_event_notifier_group(struct ust_app *app)
 			event_pipe_write_fd, &event_notifier_group);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -LTTNG_UST_ERR_EXITING && ret != -EPIPE) {
-			ERR("Failed to create application event notifier group: ret = %d, app socket fd = %d, event_pipe_write_fd = %d",
-					ret, app->sock, event_pipe_write_fd);
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			ret = 0;
+			DBG3("UST app create event notifier group failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			ret = 0;
+			WARN("UST app create event notifier group failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
 		} else {
-			DBG("Failed to create application event notifier group (application is dead): app socket fd = %d",
-					app->sock);
+			ERR("UST app create event notifier group failed with ret %d: pid = %d, sock = %d, event_pipe_write_fd: %d",
+					ret, app->pid, app->sock, event_pipe_write_fd);
 		}
-
 		goto error;
 	}
 
 	ret = lttng_pipe_write_close(app->event_notifier_group.event_pipe);
 	if (ret) {
-		ERR("Failed to close write end of the application's event source pipe: app = '%s' (ppid = %d)",
-				app->name, app->ppid);
+		ERR("Failed to close write end of the application's event source pipe: app = '%s' (pid = %d)",
+				app->name, app->pid);
 		goto error;
 	}
 
@@ -4099,13 +4192,13 @@ int ust_app_setup_event_notifier_group(struct ust_app *app)
 	case EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_OK:
 		break;
 	case EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_UNSUPPORTED:
-		DBG3("Failed to setup event notifier error accounting (application does not support notifier error accounting): app socket fd = %d, app name = '%s', app ppid = %d",
-				app->sock, app->name, (int) app->ppid);
+		DBG3("Failed to setup event notifier error accounting (application does not support notifier error accounting): app socket fd = %d, app name = '%s', app pid = %d",
+				app->sock, app->name, (int) app->pid);
 		ret = 0;
 		goto error_accounting;
 	case EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_APP_DEAD:
-		DBG3("Failed to setup event notifier error accounting (application is dead): app socket fd = %d, app name = '%s', app ppid = %d",
-				app->sock, app->name, (int) app->ppid);
+		DBG3("Failed to setup event notifier error accounting (application is dead): app socket fd = %d, app name = '%s', app pid = %d",
+				app->sock, app->name, (int) app->pid);
 		ret = 0;
 		goto error_accounting;
 	default:
@@ -4307,11 +4400,6 @@ 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;
 				}
 				free(tmp_event);
@@ -4366,8 +4454,17 @@ int ust_app_list_events(struct lttng_event **events)
 		}
 		ret = lttng_ust_ctl_release_handle(app->sock, handle);
 		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0 && ret != -LTTNG_UST_ERR_EXITING && ret != -EPIPE) {
-			ERR("Error releasing app handle for app %d with ret %d", app->sock, ret);
+		if (ret < 0) {
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("Error releasing app handle. Application died: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else if (ret == -EAGAIN) {
+				WARN("Error releasing app handle. Communication time out: pid = %d, sock = %d",
+						app->pid, app->sock);
+			} else {
+				ERR("Error releasing app handle with ret %d: pid = %d, sock = %d",
+						ret, app->pid, app->sock);
+			}
 		}
 	}
 
@@ -4438,11 +4535,6 @@ 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. Reset list and count for next app.
-					 */
 					break;
 				}
 				free(tmp_event);
@@ -5047,18 +5139,20 @@ skip_setup:
 	ret = lttng_ust_ctl_start_session(app->sock, ua_sess->handle);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Error starting tracing for app pid: %d (ret: %d)",
-					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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app start session failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
 			pthread_mutex_unlock(&ua_sess->lock);
 			goto end;
+		} else if (ret == -EAGAIN) {
+			WARN("UST app start session failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+			pthread_mutex_unlock(&ua_sess->lock);
+			goto end;
+
+		} else {
+			ERR("UST app start session failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		goto error_unlock;
 	}
@@ -5075,9 +5169,17 @@ skip_setup:
 	pthread_mutex_lock(&app->sock_lock);
 	ret = lttng_ust_ctl_wait_quiescent(app->sock);
 	pthread_mutex_unlock(&app->sock_lock);
-	if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-		ERR("UST app wait quiescent failed for app pid %d ret %d",
-				app->pid, ret);
+	if (ret < 0) {
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app wait quiescent failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app wait quiescent failed. Communication time out: pid =  %d, sock = %d",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app wait quiescent failed with ret %d: pid %d, sock = %d",
+					ret, app->pid, app->sock);
+		}
 	}
 
 end:
@@ -5139,17 +5241,18 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	ret = lttng_ust_ctl_stop_session(app->sock, ua_sess->handle);
 	pthread_mutex_unlock(&app->sock_lock);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("Error stopping tracing for app pid: %d (ret: %d)",
-					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.
-			 */
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app stop session failed. Application is dead: pid = %d, sock = %d",
+					app->pid, app->sock);
 			goto end_unlock;
+		} else if (ret == -EAGAIN) {
+			WARN("UST app stop session failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
+			goto end_unlock;
+
+		} else {
+			ERR("UST app stop session failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		goto error_rcu_unlock;
 	}
@@ -5161,9 +5264,17 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	pthread_mutex_lock(&app->sock_lock);
 	ret = lttng_ust_ctl_wait_quiescent(app->sock);
 	pthread_mutex_unlock(&app->sock_lock);
-	if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-		ERR("UST app wait quiescent failed for app pid %d ret %d",
-				app->pid, ret);
+	if (ret < 0) {
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app wait quiescent failed. Application is dead: pid= %d, sock = %d)",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app wait quiescent failed. Communication time out: pid= %d, sock = %d)",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app wait quiescent failed with ret %d: pid= %d, sock = %d)",
+					ret, app->pid, app->sock);
+		}
 	}
 
 	health_code_update();
@@ -5511,9 +5622,17 @@ static int destroy_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	pthread_mutex_lock(&app->sock_lock);
 	ret = lttng_ust_ctl_wait_quiescent(app->sock);
 	pthread_mutex_unlock(&app->sock_lock);
-	if (ret < 0 && ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-		ERR("UST app wait quiescent failed for app pid %d ret %d",
-				app->pid, ret);
+	if (ret < 0) {
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app wait quiescent failed. Application is dead: pid= %d, sock = %d)",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app wait quiescent failed. Communication time out: pid= %d, sock = %d)",
+					app->pid, app->sock);
+		} else {
+			ERR("UST app wait quiescent failed with ret %d: pid= %d, sock = %d)",
+					ret, app->pid, app->sock);
+		}
 	}
 end:
 	rcu_read_unlock();
@@ -5999,16 +6118,16 @@ void ust_app_global_update(struct ltt_ust_session *usess, struct ust_app *app)
  */
 void ust_app_global_update_event_notifier_rules(struct ust_app *app)
 {
-	DBG2("UST application global event notifier rules update: app = '%s' (ppid: %d)",
-			app->name, app->ppid);
+	DBG2("UST application global event notifier rules update: app = '%s', pid = %d)",
+			app->name, app->pid);
 
 	if (!app->compatible || !ust_app_supports_notifiers(app)) {
 		return;
 	}
 
 	if (app->event_notifier_group.object == NULL) {
-		WARN("UST app global update of event notifiers for app skipped since communication handle is null: app = '%s' (ppid: %d)",
-				app->name, app->ppid);
+		WARN("UST app global update of event notifiers for app skipped since communication handle is null: app = '%s' pid = %d)",
+				app->name, app->pid);
 		return;
 	}
 
@@ -6294,15 +6413,20 @@ static int reply_ust_register_channel(int sock, int cobjd,
 
 reply:
 	DBG3("UST app replying to register channel key %" PRIu64
-			" with id %u, type: %d, ret: %d", chan_reg_key, chan_id, type,
+			" with id %u, type = %d, ret = %d", chan_reg_key, chan_id, type,
 			ret_code);
 
 	ret = lttng_ust_ctl_reply_register_channel(sock, chan_id, type, ret_code);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app reply channel failed with ret %d", ret);
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app reply channel failed. Application died: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app reply channel failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
 		} else {
-			DBG3("UST app reply channel failed. Application died");
+			ERR("UST app reply channel failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		goto error;
 	}
@@ -6396,10 +6520,15 @@ static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name,
 	 */
 	ret = lttng_ust_ctl_reply_register_event(sock, event_id, ret_code);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app reply event failed with ret %d", ret);
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app reply event failed. Application died: pid = %d, sock = %d.",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app reply event failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
 		} else {
-			DBG3("UST app reply event failed. Application died");
+			ERR("UST app reply event failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		/*
 		 * No need to wipe the create event since the application socket will
@@ -6454,14 +6583,14 @@ static int add_enum_ust_registry(int sock, int sobjd, char *name,
 	ua_sess = find_session_by_objd(app, sobjd);
 	if (!ua_sess) {
 		/* Return an error since this is not an error */
-		DBG("Application session is being torn down (session not found). Aborting enum registration.");
+		DBG("Application session is being torn down (session not found Aborting enum registration.");
 		free(entries);
 		goto error_rcu_unlock;
 	}
 
 	registry = get_session_registry(ua_sess);
 	if (!registry) {
-		DBG("Application session is being torn down (registry not found). Aborting enum registration.");
+		DBG("Application session is being torn down (registry not found Aborting enum registration.");
 		free(entries);
 		goto error_rcu_unlock;
 	}
@@ -6484,10 +6613,15 @@ static int add_enum_ust_registry(int sock, int sobjd, char *name,
 	 */
 	ret = lttng_ust_ctl_reply_register_enum(sock, enum_id, ret_code);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app reply enum failed with ret %d", ret);
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app reply enum failed. Application died: pid = %d, sock = %d",
+					app->pid, app->sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app reply enum failed. Communication time out: pid = %d, sock = %d",
+					app->pid, app->sock);
 		} else {
-			DBG3("UST app reply enum failed. Application died");
+			ERR("UST app reply enum failed with ret %d: pid = %d, sock = %d",
+					ret, app->pid, app->sock);
 		}
 		/*
 		 * No need to wipe the create enum since the application socket will
@@ -6519,10 +6653,15 @@ int ust_app_recv_notify(int sock)
 
 	ret = lttng_ust_ctl_recv_notify(sock, &cmd);
 	if (ret < 0) {
-		if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-			ERR("UST app recv notify failed with ret %d", ret);
+		if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+			DBG3("UST app recv notify failed. Application died: sock = %d",
+					sock);
+		} else if (ret == -EAGAIN) {
+			WARN("UST app recv notify failed. Communication time out: sock = %d",
+					sock);
 		} else {
-			DBG3("UST app recv notify failed. Application died");
+			ERR("UST app recv notify failed with ret %d: sock = %d",
+					ret, sock);
 		}
 		goto error;
 	}
@@ -6541,10 +6680,15 @@ int ust_app_recv_notify(int sock)
 				&loglevel_value, &sig, &nr_fields, &fields,
 				&model_emf_uri);
 		if (ret < 0) {
-			if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-				ERR("UST app recv event failed with ret %d", ret);
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app recv event failed. Application died: sock = %d",
+						sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app recv event failed. Communication time out: sock = %d",
+						sock);
 			} else {
-				DBG3("UST app recv event failed. Application died");
+				ERR("UST app recv event failed with ret %d: sock = %d",
+						ret, sock);
 			}
 			goto error;
 		}
@@ -6574,10 +6718,15 @@ int ust_app_recv_notify(int sock)
 		ret = lttng_ust_ctl_recv_register_channel(sock, &sobjd, &cobjd, &nr_fields,
 				&fields);
 		if (ret < 0) {
-			if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-				ERR("UST app recv channel failed with ret %d", ret);
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app recv channel failed. Application died: sock = %d",
+						sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app recv channel failed. Communication time out: sock = %d",
+						sock);
 			} else {
-				DBG3("UST app recv channel failed. Application died");
+				ERR("UST app recv channel failed with ret %d: sock = %d)",
+						ret, sock);
 			}
 			goto error;
 		}
@@ -6607,10 +6756,15 @@ int ust_app_recv_notify(int sock)
 		ret = lttng_ust_ctl_recv_register_enum(sock, &sobjd, name,
 				&entries, &nr_entries);
 		if (ret < 0) {
-			if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
-				ERR("UST app recv enum failed with ret %d", ret);
+			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
+				DBG3("UST app recv enum failed. Application died: sock = %d",
+						sock);
+			} else if (ret == -EAGAIN) {
+				WARN("UST app recv enum failed. Communication time out: sock = %d",
+						sock);
 			} else {
-				DBG3("UST app recv enum failed. Application died");
+				ERR("UST app recv enum failed with ret %d: sock = %d",
+						ret, sock);
 			}
 			goto error;
 		}