diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index c472f97..3bc6069 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -48,6 +48,9 @@
 extern struct file_operations proc_cpuset_operations;
 extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer);
 
+extern void cpuset_lock(void);
+extern void cpuset_unlock(void);
+
 #else /* !CONFIG_CPUSETS */
 
 static inline int cpuset_init_early(void) { return 0; }
@@ -93,6 +96,9 @@
 	return buffer;
 }
 
+static inline void cpuset_lock(void) {}
+static inline void cpuset_unlock(void) {}
+
 #endif /* !CONFIG_CPUSETS */
 
 #endif /* _LINUX_CPUSET_H */
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d4b6bd7..fe2f71f 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2150,6 +2150,33 @@
 }
 
 /**
+ * cpuset_lock - lock out any changes to cpuset structures
+ *
+ * The out of memory (oom) code needs to lock down cpusets
+ * from being changed while it scans the tasklist looking for a
+ * task in an overlapping cpuset.  Expose callback_sem via this
+ * cpuset_lock() routine, so the oom code can lock it, before
+ * locking the task list.  The tasklist_lock is a spinlock, so
+ * must be taken inside callback_sem.
+ */
+
+void cpuset_lock(void)
+{
+	down(&callback_sem);
+}
+
+/**
+ * cpuset_unlock - release lock on cpuset changes
+ *
+ * Undo the lock taken in a previous cpuset_lock() call.
+ */
+
+void cpuset_unlock(void)
+{
+	up(&callback_sem);
+}
+
+/**
  * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
  * @p: pointer to task_struct of some other task.
  *
@@ -2158,7 +2185,7 @@
  * determine if task @p's memory usage might impact the memory
  * available to the current task.
  *
- * Acquires callback_sem - not suitable for calling from a fast path.
+ * Call while holding callback_sem.
  **/
 
 int cpuset_excl_nodes_overlap(const struct task_struct *p)
@@ -2166,8 +2193,6 @@
 	const struct cpuset *cs1, *cs2;	/* my and p's cpuset ancestors */
 	int overlap = 0;		/* do cpusets overlap? */
 
-	down(&callback_sem);
-
 	task_lock(current);
 	if (current->flags & PF_EXITING) {
 		task_unlock(current);
@@ -2186,8 +2211,6 @@
 
 	overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
 done:
-	up(&callback_sem);
-
 	return overlap;
 }
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 4748b90..14bd4ec 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -274,6 +274,7 @@
 		show_mem();
 	}
 
+	cpuset_lock();
 	read_lock(&tasklist_lock);
 retry:
 	p = select_bad_process();
@@ -284,6 +285,7 @@
 	/* Found nothing?!?! Either we hang forever, or we panic. */
 	if (!p) {
 		read_unlock(&tasklist_lock);
+		cpuset_unlock();
 		panic("Out of memory and no killable processes...\n");
 	}
 
@@ -293,6 +295,7 @@
 
  out:
 	read_unlock(&tasklist_lock);
+	cpuset_unlock();
 	if (mm)
 		mmput(mm);