From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Thu, 9 Aug 2018 21:21:40 +0000 (-0400)
Subject: Fix: Skip uid registry when metadata key value is 0
X-Git-Tag: v2.12.0-rc1~100
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=14d3fca9eddbb059a9dae789affd561cf87337e4;ds=sidebyside

Fix: Skip uid registry when metadata key value is 0

A value of 0 for the metadata key indicates that the metadata channel
was never created/pushed on the consumer side.

This can occur in scenario where a tracker(s) (vuid/vgid/vpid) is present.
The metadata channel might never be created/pushed since no applications
are actually tracing. Still, the uid registry exists due to the order
in which the sessiond received the client commands (create,
enable-channel, lttng track/untrack).

See included test for a complete reproducer.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: Id7ef34ebc48333f47db4bdca907cf81911b60d1d
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index d0980220d..b1dba0a09 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -6343,6 +6343,11 @@ enum lttng_error_code ust_app_rotate_session(struct ltt_session *session)
 			struct buffer_reg_channel *reg_chan;
 			struct consumer_socket *socket;
 
+			if (!reg->registry->reg.ust->metadata_key) {
+				/* Skip since no metadata is present */
+				continue;
+			}
+
 			/* Get consumer socket to use to push the metadata.*/
 			socket = consumer_find_socket_by_bitness(reg->bits_per_long,
 					usess->consumer);
diff --git a/tests/regression/tools/tracker/test_event_tracker b/tests/regression/tools/tracker/test_event_tracker
index 0daa2f8b5..b4563b333 100755
--- a/tests/regression/tools/tracker/test_event_tracker
+++ b/tests/regression/tools/tracker/test_event_tracker
@@ -28,7 +28,7 @@ TESTAPP_KERNEL_BIN="$TESTAPP_PATH/$TESTAPP_KERNEL_NAME/$TESTAPP_KERNEL_NAME"
 SESSION_NAME="tracker"
 NR_ITER=100
 NUM_GLOBAL_TESTS=2
-NUM_UST_TESTS=256
+NUM_UST_TESTS=265
 NUM_KERNEL_TESTS=462
 NUM_TESTS=$((NUM_UST_TESTS+NUM_KERNEL_TESTS+NUM_GLOBAL_TESTS))
 
@@ -345,6 +345,36 @@ function test_event_pid_track_untrack()
 	rm -rf "$trace_path"
 }
 
+function test_event_ust_vpid_untrack_snapshot()
+{
+	local trace_path
+
+	trace_path=$(mktemp -d)
+
+	diag "Test_event_ust_vpid_untrack_snapshot"
+
+	create_lttng_session_ok $SESSION_NAME "$trace_path" "--snapshot"
+
+	enable_ust_lttng_event_ok $SESSION_NAME "$EVENT_NAME"
+
+	prepare_ust_app
+
+	lttng_untrack_ust_ok "--vpid --all"
+
+	start_lttng_tracing_ok
+
+	trace_ust_app
+	lttng_snapshot_record $SESSION_NAME
+
+	stop_lttng_tracing_ok
+	destroy_lttng_session_ok $SESSION_NAME
+
+	snapshot_count=$(find "$trace_path" -name metadata | wc -l)
+	is "$snapshot_count" 0 "Number of snapshot is zero"
+
+	rm -rf "$trace_path"
+}
+
 # MUST set TESTDIR before calling those functions
 plan_tests $NUM_TESTS
 
@@ -402,6 +432,10 @@ test_event_vpid_track_untrack ust 0 "${EVENT_NAME}"
 test_event_tracker ust 1 "${EVENT_NAME}" "--vpid --all"
 test_event_vpid_tracker ust 1 "${EVENT_NAME}"
 
+#snapshot untrack vpid
+
+test_event_ust_vpid_untrack_snapshot
+
 #pid (backward compat)
 
 #non-matching