---

yaml
---
r: 4291
b: refs/heads/master
c: 1ce88cf
h: refs/heads/master
i:
  4289: 2772d0b
  4287: 9ae6675
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 202322e6f7cd12e82b5ff0fa92bbdf517fcf0947
+refs/heads/master: 1ce88cf466f7b6078b14d67d186a3d7c19dd5609

trunk/fs/namespace.c

@@ -869,7 +869,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
 		/* don't do anything if the namespace is dead - all the
 		 * vfsmounts from it are going away anyway */
 		namespace = mnt->mnt_namespace;
-		if (!namespace || atomic_read(&namespace->count) <= 0)
+		if (!namespace || !namespace->root)
 			continue;
 		get_namespace(namespace);
 
@@ -1450,9 +1450,12 @@ void __init mnt_init(unsigned long mempages)
 
 void __put_namespace(struct namespace *namespace)
 {
+	struct vfsmount *root = namespace->root;
+	namespace->root = NULL;
+	spin_unlock(&vfsmount_lock);
 	down_write(&namespace->sem);
 	spin_lock(&vfsmount_lock);
-	umount_tree(namespace->root);
+	umount_tree(root);
 	spin_unlock(&vfsmount_lock);
 	up_write(&namespace->sem);
 	kfree(namespace);

trunk/include/linux/namespace.h

@@ -17,7 +17,8 @@ extern void __put_namespace(struct namespace *namespace);
 
 static inline void put_namespace(struct namespace *namespace)
 {
-	if (atomic_dec_and_test(&namespace->count))
+	if (atomic_dec_and_lock(&namespace->count, &vfsmount_lock))
+		/* releases vfsmount_lock */
 		__put_namespace(namespace);
 }