diff --git a/[refs] b/[refs]
index 2cd34599e675..1ff37707d0a4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8cd9c249128a59e8e833d454a784b0cbd338d468
+refs/heads/master: c5f1cc8c1828486a61ab3e575da6e2c62b34d399
diff --git a/trunk/fs/exec.c b/trunk/fs/exec.c
index c74bb34eeeff..15d493fe8aa3 100644
--- a/trunk/fs/exec.c
+++ b/trunk/fs/exec.c
@@ -1591,7 +1591,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
 	}
 	rcu_read_unlock();
 done:
-	core_state->nr_threads = nr;
+	atomic_set(&core_state->nr_threads, nr);
 	return nr;
 }
 
diff --git a/trunk/include/linux/mm_types.h b/trunk/include/linux/mm_types.h
index c0b1747b61a5..ae99a28ba6ae 100644
--- a/trunk/include/linux/mm_types.h
+++ b/trunk/include/linux/mm_types.h
@@ -160,7 +160,7 @@ struct vm_area_struct {
 };
 
 struct core_state {
-	int nr_threads;
+	atomic_t nr_threads;
 	struct completion startup;
 };
 
diff --git a/trunk/kernel/exit.c b/trunk/kernel/exit.c
index 988e232254e9..63d82957baae 100644
--- a/trunk/kernel/exit.c
+++ b/trunk/kernel/exit.c
@@ -678,10 +678,9 @@ static void exit_mm(struct task_struct * tsk)
 	down_read(&mm->mmap_sem);
 	if (mm->core_state) {
 		up_read(&mm->mmap_sem);
-		down_write(&mm->mmap_sem);
-		if (!--mm->core_state->nr_threads)
+
+		if (atomic_dec_and_test(&mm->core_state->nr_threads))
 			complete(&mm->core_state->startup);
-		up_write(&mm->mmap_sem);
 
 		wait_for_completion(&mm->core_done);
 		down_read(&mm->mmap_sem);