1 files changed, 6 insertions, 2 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 9ff173dca1ae..4ab4c3766a80 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -64,7 +64,7 @@ static inline struct kthread *to_kthread(struct task_struct *k)
 static struct kthread *to_live_kthread(struct task_struct *k)
 {
         struct completion *vfork = ACCESS_ONCE(k->vfork_done);
-        if (likely(vfork))
+        if (likely(vfork) && try_get_task_stack(k))
                 return __to_kthread(vfork);
         return NULL;
 }
@@ -425,8 +425,10 @@ void kthread_unpark(struct task_struct *k)
 {
         struct kthread *kthread = to_live_kthread(k);
 
-        if (kthread)
+        if (kthread) {
                 __kthread_unpark(k, kthread);
+                put_task_stack(k);
+        }
 }
 EXPORT_SYMBOL_GPL(kthread_unpark);
 
@@ -455,6 +457,7 @@ int kthread_park(struct task_struct *k)
                                 wait_for_completion(&kthread->parked);
                         }
                 }
+                put_task_stack(k);
                 ret = 0;
         }
         return ret;
@@ -490,6 +493,7 @@ int kthread_stop(struct task_struct *k)
                 __kthread_unpark(k, kthread);
                 wake_up_process(k);
                 wait_for_completion(&kthread->exited);
+                put_task_stack(k);
         }
         ret = k->exit_code;
         put_task_struct(k);