---

yaml
---
r: 121154
b: refs/heads/master
c: 86fa2f6
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a22506347d038a66506c6f57e9b97104128e280d
+refs/heads/master: 86fa2f60674540df0b34f5c547ed0c1cf3a8f212

trunk/kernel/trace/trace.c

@@ -520,7 +520,15 @@ int register_tracer(struct tracer *type)
 		return -1;
 	}
 
+	/*
+	 * When this gets called we hold the BKL which means that
+	 * preemption is disabled. Various trace selftests however
+	 * need to disable and enable preemption for successful tests.
+	 * So we drop the BKL here and grab it after the tests again.
+	 */
+	unlock_kernel();
 	mutex_lock(&trace_types_lock);
+
 	for (t = trace_types; t; t = t->next) {
 		if (strcmp(type->name, t->name) == 0) {
 			/* already found */
@@ -532,13 +540,6 @@ int register_tracer(struct tracer *type)
 	}
 
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-	/*
-	 * When this gets called we hold the BKL which means that preemption
-	 * is disabled. Various trace selftests however need to disable
-	 * and enable preemption for successful tests. So we drop the BKL here
-	 * and grab it after the tests again.
-	 */
-	unlock_kernel();
 	if (type->selftest) {
 		struct tracer *saved_tracer = current_trace;
 		struct trace_array *tr = &global_trace;
@@ -550,9 +551,9 @@ int register_tracer(struct tracer *type)
 		 * internal tracing to verify that everything is in order.
 		 * If we fail, we do not register this tracer.
 		 */
-		for_each_tracing_cpu(i) {
+		for_each_tracing_cpu(i)
 			tracing_reset(tr, i);
-		}
+
 		current_trace = type;
 		/* the test is responsible for initializing and enabling */
 		pr_info("Testing tracer %s: ", type->name);
@@ -564,12 +565,11 @@ int register_tracer(struct tracer *type)
 			goto out;
 		}
 		/* Only reset on passing, to avoid touching corrupted buffers */
-		for_each_tracing_cpu(i) {
+		for_each_tracing_cpu(i)
 			tracing_reset(tr, i);
-		}
+
 		printk(KERN_CONT "PASSED\n");
 	}
-	lock_kernel();
 #endif
 
 	type->next = trace_types;
@@ -580,6 +580,7 @@ int register_tracer(struct tracer *type)
 
  out:
 	mutex_unlock(&trace_types_lock);
+	lock_kernel();
 
 	return ret;
 }