diff --git a/[refs] b/[refs]
index 02ca2f54b8f8..7e3ff072668f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 86f82d561864e902c70282b6f17cf590c0f34691
+refs/heads/master: c4c27fbdda4e8ba87806c415b6d15266b07bce4b
diff --git a/trunk/kernel/cgroup.c b/trunk/kernel/cgroup.c
index b2f203f25ec8..ad8eae5bb801 100644
--- a/trunk/kernel/cgroup.c
+++ b/trunk/kernel/cgroup.c
@@ -60,6 +60,7 @@
 #include <linux/eventfd.h>
 #include <linux/poll.h>
 #include <linux/flex_array.h> /* used in cgroup_attach_proc */
+#include <linux/kthread.h>
 
 #include <linux/atomic.h>
 
@@ -2225,6 +2226,18 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid, bool threadgroup)
 
 	if (threadgroup)
 		tsk = tsk->group_leader;
+
+	/*
+	 * Workqueue threads may acquire PF_THREAD_BOUND and become
+	 * trapped in a cpuset, or RT worker may be born in a cgroup
+	 * with no rt_runtime allocated.  Just say no.
+	 */
+	if (tsk == kthreadd_task || (tsk->flags & PF_THREAD_BOUND)) {
+		ret = -EINVAL;
+		rcu_read_unlock();
+		goto out_unlock_cgroup;
+	}
+
 	get_task_struct(tsk);
 	rcu_read_unlock();