X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=probes%2Flttng-ftrace.c;h=1aa71831e86fd4bd21780278bb78d385f79ebc8b;hb=6af0c092e6e2dd7f3441934fad44faac61fa2ef9;hp=476d6bce8e50600e0a6691317e3fd39d044c1c1b;hpb=f167620537b558f8fabd6912d4ea5c46a92cd877;p=lttng-modules.git

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 476d6bce..1aa71831 100644
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -11,6 +11,10 @@
  * Ftrace function tracer does not seem to provide synchronization between probe
  * teardown and callback execution. Therefore, we make this module permanently
  * loaded (unloadable).
+ *
+ * TODO: Move to register_ftrace_function() (which is exported for
+ * modules) for Linux >= 3.0. It is faster (only enables the selected
+ * functions), and will stay there.
  */
 
 #include <linux/module.h>
@@ -34,8 +38,13 @@ void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data
 	} payload;
 	int ret;
 
-	if (!ACCESS_ONCE(chan->session->active))
+	if (unlikely(!ACCESS_ONCE(chan->session->active)))
+		return;
+	if (unlikely(!ACCESS_ONCE(chan->enabled)))
 		return;
+	if (unlikely(!ACCESS_ONCE(event->enabled)))
+		return;
+
 	lib_ring_buffer_ctx_init(&ctx, chan->chan, event,
 				 sizeof(payload), ltt_alignof(payload), -1);
 	ret = chan->ops->event_reserve(&ctx, event->id);