From: David Goulet <dgoulet@efficios.com>
Date: Wed, 11 Jan 2012 20:21:58 +0000 (-0500)
Subject: Add missing rcu read lock and add assert
X-Git-Tag: v2.0-pre17~27
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=24d1723f7e614f74b6957ad3f3666a5713664d63

Add missing rcu read lock and add assert

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/lttng-sessiond/channel.c b/lttng-sessiond/channel.c
index 7ff974da0..b4dc48d16 100644
--- a/lttng-sessiond/channel.c
+++ b/lttng-sessiond/channel.c
@@ -266,6 +266,10 @@ int channel_ust_create(struct ltt_ust_session *usess, int domain,
 	return LTTCOMM_OK;
 
 error_free_chan:
+	/*
+	 * No need to remove the channel from the hash table because at this point
+	 * it was not added hence the direct call and no call_rcu().
+	 */
 	trace_ust_destroy_channel(uchan);
 error:
 	free(defattr);
diff --git a/lttng-sessiond/trace-ust.c b/lttng-sessiond/trace-ust.c
index 0bfcc3bd8..e4a521811 100644
--- a/lttng-sessiond/trace-ust.c
+++ b/lttng-sessiond/trace-ust.c
@@ -396,9 +396,8 @@ void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
 
 	cds_lfht_for_each_entry(channel->events->ht, &iter.iter, node, node) {
 		ret = lttng_ht_del(channel->events, &iter);
-		if (!ret) {
-			destroy_event(channel->events);
-		}
+		assert(!ret);
+		destroy_event(channel->events);
 	}
 
 	destroy_context(channel->ctx);
@@ -439,6 +438,8 @@ static void destroy_channels(struct lttng_ht *channels)
 	struct lttng_ht_node_str *node;
 	struct lttng_ht_iter iter;
 
+	rcu_read_lock();
+
 	cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
 		ret = lttng_ht_del(channels, &iter);
 		if (!ret) {
@@ -447,6 +448,8 @@ static void destroy_channels(struct lttng_ht *channels)
 	}
 
 	lttng_ht_destroy(channels);
+
+	rcu_read_unlock();
 }
 
 /*