1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index e75950a1092c..c5f3c6613b6d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -12,6 +12,7 @@
 #include <linux/unistd.h>
 #include <linux/file.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <asm/semaphore.h>
 
 /*
@@ -41,7 +42,7 @@ struct kthread_stop_info
 
 /* Thread stopping is done by setthing this var: lock serializes
  * multiple kthread_stop calls. */
-static DECLARE_MUTEX(kthread_stop_lock);
+static DEFINE_MUTEX(kthread_stop_lock);
 static struct kthread_stop_info kthread_stop_info;
 
 int kthread_should_stop(void)
@@ -114,7 +115,9 @@ static void keventd_create_kthread(void *_create)
                 create->result = ERR_PTR(pid);
         } else {
                 wait_for_completion(&create->started);
+                read_lock(&tasklist_lock);
                 create->result = find_task_by_pid(pid);
+                read_unlock(&tasklist_lock);
         }
         complete(&create->done);
 }
@@ -173,7 +176,7 @@ int kthread_stop_sem(struct task_struct *k, struct semaphore *s)
 {
         int ret;
 
-        down(&kthread_stop_lock);
+        mutex_lock(&kthread_stop_lock);
 
         /* It could exit after stop_info.k set, but before wake_up_process. */
         get_task_struct(k);
@@ -194,7 +197,7 @@ int kthread_stop_sem(struct task_struct *k, struct semaphore *s)
         wait_for_completion(&kthread_stop_info.done);
         kthread_stop_info.k = NULL;
         ret = kthread_stop_info.err;
-        up(&kthread_stop_lock);
+        mutex_unlock(&kthread_stop_lock);
 
         return ret;
 }