From: David Goulet <dgoulet@efficios.com>
Date: Mon, 22 Oct 2012 21:16:38 +0000 (-0400)
Subject: Fix: Mutex and RCU lock nesting in consumer
X-Git-Tag: v2.1.0-rc6~29
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=6f6eda74c76594068cd8c435c62bf8100a9d734a

Fix: Mutex and RCU lock nesting in consumer

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

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 132e3ec68..295e7be5d 100644
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -1266,11 +1266,11 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 	lttng_consumer_sync_trace_file(stream, orig_offset);
 
 end:
-	pthread_mutex_unlock(&stream->lock);
 	/* Unlock only if ctrl socket used */
 	if (relayd && stream->metadata_flag) {
 		pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 	}
+	pthread_mutex_unlock(&stream->lock);
 
 	rcu_read_unlock();
 	return written;
@@ -1451,10 +1451,10 @@ splice_error:
 	}
 
 end:
-	pthread_mutex_unlock(&stream->lock);
 	if (relayd && stream->metadata_flag) {
 		pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 	}
+	pthread_mutex_unlock(&stream->lock);
 
 	rcu_read_unlock();
 	return written;
@@ -2462,6 +2462,7 @@ int consumer_data_available(uint64_t id)
 
 	DBG("Consumer data available command on session id %" PRIu64, id);
 
+	rcu_read_lock();
 	pthread_mutex_lock(&consumer_data.lock);
 
 	switch (consumer_data.type) {
@@ -2477,8 +2478,6 @@ int consumer_data_available(uint64_t id)
 		assert(0);
 	}
 
-	rcu_read_lock();
-
 	/* Ease our life a bit */
 	ht = consumer_data.stream_list_ht;