X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=probes%2Flttng-kprobes.c;h=8e1ae832cd82abb14d0413a1aee5b13cb1cd9fc8;hb=09d8de2b842b6ead8822172adb56ae3ed4c1fdfa;hp=89cfe07364779f6a2094979b16c6f039252fac89;hpb=f167620537b558f8fabd6912d4ea5c46a92cd877;p=lttng-modules.git

diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index 89cfe073..8e1ae832 100644
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -25,8 +25,13 @@ int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
 	int ret;
 	unsigned long data = (unsigned long) p->addr;
 
-	if (!ACCESS_ONCE(chan->session->active))
+	if (unlikely(!ACCESS_ONCE(chan->session->active)))
 		return 0;
+	if (unlikely(!ACCESS_ONCE(chan->enabled)))
+		return 0;
+	if (unlikely(!ACCESS_ONCE(event->enabled)))
+		return 0;
+
 	lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(data),
 				 ltt_alignof(data), -1);
 	ret = chan->ops->event_reserve(&ctx, event->id);
@@ -91,22 +96,28 @@ int lttng_kprobes_register(const char *name,
 {
 	int ret;
 
+	/* Kprobes expects a NULL symbol name if unused */
+	if (symbol_name[0] == '\0')
+		symbol_name = NULL;
+
 	ret = lttng_create_kprobe_event(name, event);
 	if (ret)
 		goto error;
 	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
 	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
-	event->u.kprobe.symbol_name =
-		kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
-			GFP_KERNEL);
-	if (!event->u.kprobe.symbol_name) {
-		ret = -ENOMEM;
-		goto name_error;
+	if (symbol_name) {
+		event->u.kprobe.symbol_name =
+			kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
+				GFP_KERNEL);
+		if (!event->u.kprobe.symbol_name) {
+			ret = -ENOMEM;
+			goto name_error;
+		}
+		memcpy(event->u.kprobe.symbol_name, symbol_name,
+		       LTTNG_SYM_NAME_LEN * sizeof(char));
+		event->u.kprobe.kp.symbol_name =
+			event->u.kprobe.symbol_name;
 	}
-	memcpy(event->u.kprobe.symbol_name, symbol_name,
-	       LTTNG_SYM_NAME_LEN * sizeof(char));
-	event->u.kprobe.kp.symbol_name =
-		event->u.kprobe.symbol_name;
 	event->u.kprobe.kp.offset = offset;
 	event->u.kprobe.kp.addr = (void *) addr;