From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 6 Dec 2018 20:38:14 +0000 (-0500)
Subject: Fix: ensure the ht clean pipe is empty before processing quit pipe
X-Git-Tag: v2.12.0-rc1~705
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=df119599f9c1994b5f4a9f6f562581bee13c0f13

Fix: ensure the ht clean pipe is empty before processing quit pipe

The ht-cleanup thread does not ensure that all data pending on its
ht_clean_pipe has been read (and processed) before processing the
"quit" event on the quit_pipe.

This causes a number of urcu hash tables to be leaked on exit of
the sessiond even though they have been pushed on the cleanup
pipe.

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

diff --git a/src/bin/lttng-sessiond/ht-cleanup.c b/src/bin/lttng-sessiond/ht-cleanup.c
index 09c13fe00..91c0544c3 100644
--- a/src/bin/lttng-sessiond/ht-cleanup.c
+++ b/src/bin/lttng-sessiond/ht-cleanup.c
@@ -128,6 +128,7 @@ static void *thread_ht_cleanup(void *data)
 	health_code_update();
 
 	while (1) {
+	restart:
 		DBG3("[ht-thread] Polling.");
 		health_poll_entry();
 		ret = lttng_poll_wait(&events, -1);
@@ -181,6 +182,13 @@ static void *thread_ht_cleanup(void *data)
 				lttng_ht_destroy(ht);
 
 				health_code_update();
+
+				/*
+				 * Ensure that we never process the quit pipe
+				 * event while there is still data available
+				 * on the ht clean pipe.
+				 */
+				goto restart;
 			} else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 				ERR("ht cleanup pipe error");
 				goto error;