Kconsumerd and sessiond both have reference on lttng-module. This can lead to a
race
on modprobe_remove_lttng_all which might fail to unload modules due to
certain modules not having a ref count equal to zero at the time.
waitpid is used to force a synchronization on the child (kconsumer) termination.
This also have been applied to ust consumers for the sake of consistency.
Fixes: #878
Signed-off-by: Jonathan Rajotte <jonathan.rajotte-jul...@efficios.com>
---
src/bin/lttng-sessiond/main.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index d284deb..efb00c7 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -587,6 +587,28 @@ static int generate_lock_file_path(char *path, size_t len)
}
/*
+ * Wait on consumer process termination
+ */
+static void wait_consumer(struct consumer_data *consumer_data)
+{
+ pid_t ret;
+ int status;
+ if (consumer_data->pid > 0) {
+ DBG("Waiting for complete teardown of consumerd (PID:%d)",
+ consumer_data->pid);
+ ret = waitpid(consumer_data->pid, &status, 0);
+ if (ret == -1) {
+ PERROR("consumerd waitpid pid:%d", consumer_data->pid)
+ }
+ if (!WIFEXITED(status)) {
+ PERROR("consumerd termination with error:%d",
+ WEXITSTATUS(ret));
+ }
+ consumer_data->pid = 0;
+ }
+}
+
+/*
* Cleanup the session daemon's data structures.
*/
static void sessiond_cleanup(void)
@@ -680,6 +702,11 @@ static void sessiond_cleanup(void)
}
}
+ wait_consumer(&kconsumer_data);
+ wait_consumer(&ustconsumer64_data);
+ wait_consumer(&ustconsumer32_data);
+
+
DBG("Cleaning up all agent apps");
agent_app_ht_clean();
@@ -1497,7 +1524,6 @@ error:
unlink(consumer_data->err_unix_sock_path);
unlink(consumer_data->cmd_unix_sock_path);
- consumer_data->pid = 0;
pthread_mutex_unlock(&consumer_data->lock);
/* Cleanup metadata socket mutex. */
--
2.1.4
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