diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index e7e3aa8..8d07527 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -45,8 +45,10 @@
 
 static void sysfs_kill_sb(struct super_block *sb)
 {
+	void *ns = (void *)kernfs_super_ns(sb);
+
 	kernfs_kill_sb(sb);
-	kobj_ns_drop(KOBJ_NS_TYPE_NET, (void *)kernfs_super_ns(sb));
+	kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
 }
 
 static struct file_system_type sysfs_fs_type = {