From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 19 May 2011 04:17:21 +0000 (-0400)
Subject: LTTng ftrace support module should be unloadable
X-Git-Tag: v2.0-pre1~138
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=e3de3ddef85fe03b67578e124d6af84d51198bb6;p=lttng-modules.git

LTTng ftrace support module should be unloadable

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 3ec000ae..f2190370 100644
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -7,6 +7,12 @@
  * Dual LGPL v2.1/GPL v2 license.
  */
 
+/*
+ * Ftrace function tracer does not seem to provide synchronization between probe
+ * teardown and callback execution. Therefore, we make this module permanently
+ * loaded (unloadable).
+ */
+
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/slab.h>
@@ -135,6 +141,13 @@ void lttng_ftrace_unregister(struct ltt_event *event)
 }
 EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
 
+/* This module is permanent. */
+int lttng_ftrace_init(void)
+{
+	return 0;
+}
+module_init(lttng_ftrace_init)
+
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");