[3.11.y.z extended stable] Patch "nfs4: fix discover_server_trunking use after free" has been added to staging queue

[Luis Henriques]

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

    nfs4: fix discover_server_trunking use after free

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 164642b3536a6ec5f9e930184946d535bc79401d Mon Sep 17 00:00:00 2001
From: Weston Andros Adamson <dros at primarydata.com>
Date: Sun, 19 Jan 2014 22:45:36 -0500
Subject: nfs4: fix discover_server_trunking use after free

commit abad2fa5ba67725a3f9c376c8cfe76fbe94a3041 upstream.

If clp is new (cl_count = 1) and it matches another client in
nfs4_discover_server_trunking, the nfs_put_client will free clp before
->cl_preserve_clid is set.

Signed-off-by: Weston Andros Adamson <dros at primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust at primarydata.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/nfs/nfs4client.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 3ae4d8c..069cc11 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -245,13 +245,11 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
 	error = nfs4_discover_server_trunking(clp, &old);
 	if (error < 0)
 		goto error;
-	nfs_put_client(clp);
-	if (clp != old) {
-		clp->cl_preserve_clid = true;
-		clp = old;
-	}

-	return clp;
+	if (clp != old)
+		clp->cl_preserve_clid = true;
+	nfs_put_client(clp);
+	return old;

 error:
 	nfs_mark_client_ready(clp, error);
--
1.8.3.2