diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 2efc57173fd70..266531343aae0 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -131,6 +131,8 @@ static int ramfs_nommu_check_mappings(struct inode *inode,
 	struct vm_area_struct *vma;
 	struct prio_tree_iter iter;
 
+	down_write(&nommu_region_sem);
+
 	/* search for VMAs that fall within the dead zone */
 	vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
 			      newsize >> PAGE_SHIFT,
@@ -138,10 +140,13 @@ static int ramfs_nommu_check_mappings(struct inode *inode,
 			      ) {
 		/* found one - only interested if it's shared out of the page
 		 * cache */
-		if (vma->vm_flags & VM_SHARED)
+		if (vma->vm_flags & VM_SHARED) {
+			up_write(&nommu_region_sem);
 			return -ETXTBSY; /* not quite true, but near enough */
+		}
 	}
 
+	up_write(&nommu_region_sem);
 	return 0;
 }