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=66b50eb43df98ea42c0700c5cedd5e9f28e17e8b;hb=495dece518e24e6c8563c588be77b5e23e060a02;hpb=affce97eaac76f77a3c83b1909d558b54e9a498f

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 66b50eb43..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;
 }
@@ -1100,7 +1109,7 @@ struct ust_app_event *alloc_ust_app_event(char *name,
 	/* Init most of the default value by allocating and zeroing */
 	ua_event = zmalloc(sizeof(struct ust_app_event));
 	if (ua_event == NULL) {
-		PERROR("malloc");
+		PERROR("Failed to allocate ust_app_event structure");
 		goto error;
 	}
 
@@ -3133,7 +3142,7 @@ int create_ust_app_event(struct ust_app_session *ua_sess,
 
 	ua_event = alloc_ust_app_event(uevent->attr.name, &uevent->attr);
 	if (ua_event == NULL) {
-		/* Only malloc can failed so something is really wrong */
+		/* Only failure mode of alloc_ust_app_event(). */
 		ret = -ENOMEM;
 		goto end;
 	}
@@ -3142,8 +3151,19 @@ int create_ust_app_event(struct ust_app_session *ua_sess,
 	/* Create it on the tracer side */
 	ret = create_ust_event(app, ua_sess, ua_chan, ua_event);
 	if (ret < 0) {
-		/* Not found previously means that it does not exist on the tracer */
-		assert(ret != -LTTNG_UST_ERR_EXIST);
+		/*
+		 * Not found previously means that it does not exist on the
+		 * tracer. If the application reports that the event existed,
+		 * it means there is a bug in the sessiond or lttng-ust
+		 * (or corruption, etc.)
+		 */
+		if (ret == -LTTNG_UST_ERR_EXIST) {
+			ERR("Tracer for application reported that an event being created already existed: "
+					"event_name = \"%s\", pid = %d, ppid = %d, uid = %d, gid = %d",
+					uevent->attr.name,
+					app->pid, app->ppid, app->uid,
+					app->gid);
+		}
 		goto error;
 	}
 
@@ -4201,7 +4221,7 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 			if (session_was_created) {
 				destroy_app_session(app, ua_sess);
 			}
-			goto error_rcu_unlock;
+			/* Continue to the next application. */
 		}
 	}
 
@@ -4413,7 +4433,7 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	health_code_update();
 
 skip_setup:
-	/* This start the UST tracing */
+	/* This starts the UST tracing */
 	pthread_mutex_lock(&app->sock_lock);
 	ret = ustctl_start_session(app->sock, ua_sess->handle);
 	pthread_mutex_unlock(&app->sock_lock);
@@ -6466,6 +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;