1 files changed, 13 insertions, 12 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 16892121cb7c..24b6238884f0 100644
--- a/kernel/trace/trace.c
+++ b/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;
 }