From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Sat, 12 Nov 2011 17:56:50 +0000 (-0500)
Subject: LTTng sessiond: fix ust app error handling
X-Git-Tag: v2.0-pre15~133
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=509cbaf89ee874b312c89ca8276b13569b49c4c5;hp=8bf332b9ad2aa7094c3f713399c2a3746f04a10b

LTTng sessiond: fix ust app error handling

Fix incorrect error handling of ust_app_add_channel_all and
ust_app_add_event_all commands. Make ust_app_start_trace take RCU
read-side lock, because this API is exposed outside of ust-app.c.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lttng-sessiond/main.c b/lttng-sessiond/main.c
index 5755363c8..a40c36934 100644
--- a/lttng-sessiond/main.c
+++ b/lttng-sessiond/main.c
@@ -2096,7 +2096,7 @@ static int cmd_enable_channel(struct ltt_session *session,
 
 		/* Add channel to all registered applications */
 		ret = ust_app_add_channel_all(usess, uchan);
-		if (ret != LTTCOMM_OK) {
+		if (ret != 0) {
 			goto error;
 		}
 
diff --git a/lttng-sessiond/ust-app.c b/lttng-sessiond/ust-app.c
index e063fb292..e22a5929e 100644
--- a/lttng-sessiond/ust-app.c
+++ b/lttng-sessiond/ust-app.c
@@ -808,7 +808,7 @@ int ust_app_add_channel_all(struct ltt_ust_session *usess,
 
 		/* Create session on the tracer side and add it to app session HT */
 		ua_sess = create_ust_app_session(usess, app);
-		if (ret < 0) {
+		if (ua_sess == NULL) {
 			goto next;
 		}
 
@@ -851,7 +851,7 @@ int ust_app_add_event_all(struct ltt_ust_session *usess,
 
 		/* Create session on the tracer side and add it to app session HT */
 		ua_sess = create_ust_app_session(usess, app);
-		if (ret < 0) {
+		if (ua_sess == NULL) {
 			goto next;
 		}
 
@@ -889,15 +889,17 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 
 	DBG("Starting tracing for ust app pid %d", app->key.pid);
 
+	rcu_read_lock();
+
 	ua_sess = lookup_session_by_app(usess, app);
 	if (ua_sess == NULL) {
 		/* Only malloc can failed so something is really wrong */
-		goto error;
+		goto error_rcu_unlock;
 	}
 
 	ret = create_ust_app_metadata(ua_sess, usess->pathname, app);
 	if (ret < 0) {
-		goto error;
+		goto error_rcu_unlock;
 	}
 
 	/* For each channel */
@@ -912,7 +914,7 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 			ustream = zmalloc(sizeof(*ustream));
 			if (ustream == NULL) {
 				PERROR("zmalloc ust stream");
-				continue;
+				goto error_rcu_unlock;
 			}
 
 			ret = ustctl_create_stream(app->key.sock, ua_chan->obj,
@@ -943,22 +945,24 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	/* Setup UST consumer socket and send fds to it */
 	ret = ust_consumer_send_session(usess->consumer_fd, ua_sess);
 	if (ret < 0) {
-		goto error;
+		goto error_rcu_unlock;
 	}
 
 	/* This start the UST tracing */
 	ret = ustctl_start_session(app->key.sock, ua_sess->handle);
 	if (ret < 0) {
 		ERR("Error starting tracing for app pid: %d", app->key.pid);
-		goto error;
+		goto error_rcu_unlock;
 	}
+	rcu_read_unlock();
 
 	/* Quiescent wait after starting trace */
 	ustctl_wait_quiescent(app->key.sock);
 
 	return 0;
 
-error:
+error_rcu_unlock:
+	rcu_read_unlock();
 	return -1;
 }