diff --git a/fs/exec.c b/fs/exec.c
index c74bb34eeeff032f1d45809bc2a736e15bbab8e2..15d493fe8aa3201655511b6baf3bce5caf25f5b8 100644
--- a/fs/exec.c
+++ b/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/include/linux/mm_types.h b/include/linux/mm_types.h
index c0b1747b61a5526c3aed33bb1975d46a50c7fe3b..ae99a28ba6ae4cbc5c6ca093163501254b7c2db3 100644
--- a/include/linux/mm_types.h
+++ b/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/kernel/exit.c b/kernel/exit.c
index 988e232254e9ace0cf4a4afae854c256102fb849..63d82957baae26886deaad373e6112bc6a255689 100644
--- a/kernel/exit.c
+++ b/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);