From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 2 Apr 2020 04:25:11 +0000 (-0400)
Subject: Fix: sessiond: error reported on session destruction for old modules
X-Git-Tag: v2.13.0-rc1~693
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=53fb6336415e5f19b6e8c4baeb0d0555ed5d6e66;ds=sidebyside

Fix: sessiond: error reported on session destruction for old modules

The session destruction command will return
-LTTNG_ERR_ROTATION_NOT_AVAILABLE_KERNEL when the kernel tracer
version does not support packet sequence numbers which prevents
rotations from being performed.

It is okay to not perform an implicit rotation in this case since we
know that no rotations have occurred during the session's lifetime (as
it is not supported). Thus, the client/library only needs to stop the
session, wait for pending data, and destroy the session.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ibccf73f08eecb6431ea3cc358bf8dd6af3ba4427
---

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 2bd010f89..e45d4423a 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -3402,9 +3402,17 @@ int cmd_destroy_session(struct ltt_session *session,
 		 */
 		ret = cmd_rotate_session(session, NULL, true,
 			LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION);
-		if (ret != LTTNG_OK) {
+		/*
+		 * Rotation operations may not be supported by the kernel
+		 * tracer. Hence, do not consider this implicit rotation as
+		 * a session destruction error. The library has already stopped
+		 * the session and waited for pending data; there is nothing
+		 * left to do but complete the destruction of the session.
+		 */
+		if (ret != LTTNG_OK &&
+				ret != -LTTNG_ERR_ROTATION_NOT_AVAILABLE_KERNEL) {
 			ERR("Failed to perform a quiet rotation as part of the destruction of session \"%s\": %s",
-					session->name, lttng_strerror(-ret));
+			    session->name, lttng_strerror(ret));
 			destruction_last_error = -ret;
 		}
 	}