diff --git a/mm/mmap.c b/mm/mmap.c
index 56ba432e7f1f..23698963a8ab 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3254,10 +3254,9 @@ void exit_mmap(struct mm_struct *mm)
 		(void)__oom_reap_task_mm(mm);
 
 		set_bit(MMF_OOM_SKIP, &mm->flags);
-		down_write(&mm->mmap_sem);
-		up_write(&mm->mmap_sem);
 	}
 
+	down_write(&mm->mmap_sem);
 	if (mm->locked_vm) {
 		vma = mm->mmap;
 		while (vma) {
@@ -3270,8 +3269,11 @@ void exit_mmap(struct mm_struct *mm)
 	arch_exit_mmap(mm);
 
 	vma = mm->mmap;
-	if (!vma)	/* Can happen if dup_mmap() received an OOM */
+	if (!vma) {
+		/* Can happen if dup_mmap() received an OOM */
+		up_write(&mm->mmap_sem);;
 		return;
+	}
 
 	lru_add_drain();
 	flush_cache_mm(mm);
@@ -3282,16 +3284,14 @@ void exit_mmap(struct mm_struct *mm)
 	free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
 	tlb_finish_mmu(&tlb, 0, -1);
 
-	/*
-	 * Walk the list again, actually closing and freeing it,
-	 * with preemption enabled, without holding any MM locks.
-	 */
+	/* Walk the list again, actually closing and freeing it. */
 	while (vma) {
 		if (vma->vm_flags & VM_ACCOUNT)
 			nr_accounted += vma_pages(vma);
 		vma = remove_vma(vma);
 		cond_resched();
 	}
+	up_write(&mm->mmap_sem);
 	vm_unacct_memory(nr_accounted);
 }