From e7af5374528737065dda14b486f172f07998d87e Mon Sep 17 00:00:00 2001
From: Balazs Gerofi <bgerofi@riken.jp>
Date: Sun, 25 Dec 2016 17:17:03 +0900
Subject: [PATCH] get_pid_cred(): proper locking around pid_task

---
 executer/kernel/mcctrl/procfs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/executer/kernel/mcctrl/procfs.c b/executer/kernel/mcctrl/procfs.c
index 7e5d2d8c..bee5483c 100644
--- a/executer/kernel/mcctrl/procfs.c
+++ b/executer/kernel/mcctrl/procfs.c
@@ -248,9 +248,11 @@ get_pid_cred(int pid)
 {
 	struct task_struct *task = NULL;
 
-	if(pid > 0){
+	if (pid > 0) {
+		rcu_read_lock();
 		task = pid_task(find_vpid(pid), PIDTYPE_PID);
-		if(task){
+		rcu_read_unlock();
+		if (task) {
 			return __task_cred(task);
 		}
 	}