Patch "mnt: Fix the error check in __detach_mounts" has been added to the 4.0-stable tree

This is a note to let you know that I've just added the patch titled

mnt: Fix the error check in __detach_mounts

to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mnt-fix-the-error-check-in-__detach_mounts.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "Eric W. Biederman" <[email protected]>
Date: Mon, 19 Jan 2015 11:48:45 -0600
Subject: mnt: Fix the error check in __detach_mounts

From: "Eric W. Biederman" <[email protected]>

commit f53e57975151f54ad8caa1b0ac8a78091cd5700a upstream.

lookup_mountpoint can return either NULL or an error value. Update the test in __detach_mounts to test for an error value to avoid pathological cases causing a NULL pointer dereferences.

The callers of __detach_mounts should prevent it from ever being called on an unlinked dentry but don't take any chances.

---
 fs/namespace.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1518,7 +1518,7 @@ void __detach_mounts(struct dentry *dent
 
 	namespace_lock();
 	mp = lookup_mountpoint(dentry);
-	if (!mp)
+	if (IS_ERR_OR_NULL(mp))
 		goto out_unlock;
 
 	lock_mount_hash();

Patches currently in stable-queue which might be from [email protected] are

queue-4.0/mnt-don-t-propagate-umounts-in-__detach_mounts.patch queue-4.0/mnt-add-mnt_umount-flag.patch queue-4.0/mnt-honor-mnt_locked-when-detaching-mounts.patch queue-4.0/mnt-delay-removal-from-the-mount-hash.patch queue-4.0/mnt-on-an-unmount-propagate-clearing-of-mnt_locked.patch queue-4.0/mnt-don-t-propagate-unmounts-to-locked-mounts.patch queue-4.0/mnt-factor-out-unhash_mnt-from-detach_mnt-and-umount_tree.patch queue-4.0/mnt-factor-umount_mnt-from-umount_tree.patch queue-4.0/mnt-fix-the-error-check-in-__detach_mounts.patch queue-4.0/mnt-update-detach_mounts-to-leave-mounts-connected.patch queue-4.0/mnt-improve-the-umount_tree-flags.patch queue-4.0/mnt-in-umount_tree-reuse-mnt_list-instead-of-mnt_hash.patch