X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=58308dec801f0bef53dedada426ba7bd574e51e8;hp=c03772842b88e39976716c7c9f926217d2668e04;hb=495dece518e24e6c8563c588be77b5e23e060a02;hpb=d767977450c6bf1fb18ce8bb653d6b6dfdb6bb68

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index c03772842..58308dec8 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -27,7 +27,6 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <urcu/compiler.h>
-#include <lttng/ust-error.h>
 #include <signal.h>
 
 #include <common/common.h>
@@ -38,7 +37,8 @@
 #include "health-sessiond.h"
 #include "ust-app.h"
 #include "ust-consumer.h"
-#include "ust-ctl.h"
+#include "lttng-ust-ctl.h"
+#include "lttng-ust-error.h"
 #include "utils.h"
 #include "session.h"
 #include "lttng-sessiond.h"
@@ -741,6 +741,10 @@ error:
  * nullified. The session lock MUST be held unless the application is
  * in the destroy path.
  *
+ * Do not hold the registry lock while communicating with the consumerd, because
+ * doing so causes inter-process deadlocks between consumerd and sessiond with
+ * the metadata request notification.
+ *
  * Return 0 on success else a negative value.
  */
 static int close_metadata(struct ust_registry_session *registry,
@@ -748,6 +752,8 @@ static int close_metadata(struct ust_registry_session *registry,
 {
 	int ret;
 	struct consumer_socket *socket;
+	uint64_t metadata_key;
+	bool registry_was_already_closed;
 
 	assert(registry);
 	assert(consumer);
@@ -755,8 +761,19 @@ static int close_metadata(struct ust_registry_session *registry,
 	rcu_read_lock();
 
 	pthread_mutex_lock(&registry->lock);
+	metadata_key = registry->metadata_key;
+	registry_was_already_closed = registry->metadata_closed;
+	if (metadata_key != 0) {
+		/*
+		 * Metadata closed. Even on error this means that the consumer
+		 * is not responding or not found so either way a second close
+		 * should NOT be emit for this registry.
+		 */
+		registry->metadata_closed = 1;
+	}
+	pthread_mutex_unlock(&registry->lock);
 
-	if (!registry->metadata_key || registry->metadata_closed) {
+	if (metadata_key == 0 || registry_was_already_closed) {
 		ret = 0;
 		goto end;
 	}
@@ -766,23 +783,15 @@ static int close_metadata(struct ust_registry_session *registry,
 			consumer);
 	if (!socket) {
 		ret = -1;
-		goto error;
+		goto end;
 	}
 
-	ret = consumer_close_metadata(socket, registry->metadata_key);
+	ret = consumer_close_metadata(socket, metadata_key);
 	if (ret < 0) {
-		goto error;
+		goto end;
 	}
 
-error:
-	/*
-	 * Metadata closed. Even on error this means that the consumer is not
-	 * responding or not found so either way a second close should NOT be emit
-	 * for this registry.
-	 */
-	registry->metadata_closed = 1;
 end:
-	pthread_mutex_unlock(&registry->lock);
 	rcu_read_unlock();
 	return ret;
 }
@@ -6477,6 +6486,17 @@ enum lttng_error_code ust_app_create_channel_subdirectories(
 	{
 		struct ust_app *app;
 
+		/*
+		 * Create the toplevel ust/ directory in case no apps are running.
+		 */
+		chunk_status = lttng_trace_chunk_create_subdirectory(
+				usess->current_trace_chunk,
+				DEFAULT_UST_TRACE_DIR);
+		if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+			ret = LTTNG_ERR_CREATE_DIR_FAIL;
+			goto error;
+		}
+
 		cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app,
 				pid_n.node) {
 			struct ust_app_session *ua_sess;