[4.2.y-ckt stable] Patch "do_last(): ELOOP failure exit should be done after leaving RCU mode" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    do_last(): ELOOP failure exit should be done after leaving RCU mode

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 0f4975b5c1e5b6aa2f54ba9d0198a2dd3b210f93 Mon Sep 17 00:00:00 2001
From: Al Viro <viro at zeniv.linux.org.uk>
Date: Sat, 27 Feb 2016 19:37:37 -0500
Subject: do_last(): ELOOP failure exit should be done after leaving RCU mode

commit 5129fa482b16615fd4464d2f5d23acb1b7056c66 upstream.

... or we risk seeing a bogus value of d_is_symlink() there.

Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/namei.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 414561f..7f8e493 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3152,11 +3152,6 @@ finish_lookup:
 	if (unlikely(error))
 		return error;

-	if (unlikely(d_is_symlink(path.dentry)) && !(open_flag & O_PATH)) {
-		path_to_nameidata(&path, nd);
-		return -ELOOP;
-	}
-
 	if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path.mnt) {
 		path_to_nameidata(&path, nd);
 	} else {
@@ -3175,6 +3170,10 @@ finish_open:
 		return error;
 	}
 	audit_inode(nd->name, nd->path.dentry, 0);
+	if (unlikely(d_is_symlink(nd->path.dentry)) && !(open_flag & O_PATH)) {
+		error = -ELOOP;
+		goto out;
+	}
 	error = -EISDIR;
 	if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry))
 		goto out;
--
2.7.0