diff --git a/kernel/sys.c b/kernel/sys.c
index e9ad444..7f5a0cd 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -931,6 +931,7 @@
 		pgid = pid;
 	if (pgid < 0)
 		return -EINVAL;
+	rcu_read_lock();
 
 	/* From this point forward we keep holding onto the tasklist lock
 	 * so that our parent does not change from under us. -DaveM
@@ -984,6 +985,7 @@
 out:
 	/* All paths lead to here, thus we are safe. -DaveM */
 	write_unlock_irq(&tasklist_lock);
+	rcu_read_unlock();
 	return err;
 }