From: David Goulet <dgoulet@efficios.com>
Date: Tue, 25 Feb 2014 17:21:32 +0000 (-0500)
Subject: Fix: kernel channel destroy on consumer if sent
X-Git-Tag: v2.4.0~22
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=9000e568af18bf18daf81c3d9d551d3c9a3ee56c;p=lttng-tools.git

Fix: kernel channel destroy on consumer if sent

An enable-channel immediately followed by a destroy session triggered an
assert on the consumer followed by the shutdown of the consumer thread
for the kernel.

This fix make sure we don't ask the consumer to destroy a channel if not
previously sent to it and handle not found channel on destroy.

Fixes #643

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

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index b6b24a5a2..faf35cc7f 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -759,11 +759,11 @@ void kernel_destroy_session(struct ltt_kernel_session *ksess)
 	DBG("Tearing down kernel session");
 
 	/*
-	 * Destroy channels on the consumer if in no output mode because the
-	 * streams are in *no* monitor mode so we have to send a command to clean
-	 * them up or else they leaked.
+	 * Destroy channels on the consumer if at least one FD has been sent and we
+	 * are in no output mode because the streams are in *no* monitor mode so we
+	 * have to send a command to clean them up or else they leaked.
 	 */
-	if (!ksess->output_traces) {
+	if (!ksess->output_traces && ksess->consumer_fds_sent) {
 		int ret;
 		struct consumer_socket *socket;
 		struct lttng_ht_iter iter;
diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index ab4f604d7..d15329ffa 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -918,6 +918,11 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
 		health_code_update();
 
+		/* Stop right now if no channel was found. */
+		if (!channel) {
+			goto end_nosignal;
+		}
+
 		/*
 		 * This command should ONLY be issued for channel with streams set in
 		 * no monitor mode.