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

    cgroup: initialize xattr before calling d_instantiate()

to the 3.9-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:
     cgroup-initialize-xattr-before-calling-d_instantiate.patch
and it can be found in the queue-3.9 subdirectory.

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


>From d6cbf35dac8a3dadb9103379820c96d7c85df3d9 Mon Sep 17 00:00:00 2001
From: Li Zefan <[email protected]>
Date: Tue, 14 May 2013 19:44:20 +0800
Subject: cgroup: initialize xattr before calling d_instantiate()

From: Li Zefan <[email protected]>

commit d6cbf35dac8a3dadb9103379820c96d7c85df3d9 upstream.

cgroup_create_file() calls d_instantiate(), which may decide to look
at the xattrs on the file. Smack always does this and SELinux can be
configured to do so.

But cgroup_add_file() didn't initialize xattrs before calling
cgroup_create_file(), which finally leads to dereferencing NULL
dentry->d_fsdata.

This bug has been there since cgroup xattr was introduced.

Reported-by: Ivan Bulatovic <[email protected]>
Reported-by: Casey Schaufler <[email protected]>
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 kernel/cgroup.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2747,13 +2747,14 @@ static int cgroup_add_file(struct cgroup
                goto out;
        }
 
+       cfe->type = (void *)cft;
+       cfe->dentry = dentry;
+       dentry->d_fsdata = cfe;
+       simple_xattrs_init(&cfe->xattrs);
+
        mode = cgroup_file_mode(cft);
        error = cgroup_create_file(dentry, mode | S_IFREG, cgrp->root->sb);
        if (!error) {
-               cfe->type = (void *)cft;
-               cfe->dentry = dentry;
-               dentry->d_fsdata = cfe;
-               simple_xattrs_init(&cfe->xattrs);
                list_add_tail(&cfe->node, &parent->files);
                cfe = NULL;
        }


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

queue-3.9/cgroup-initialize-xattr-before-calling-d_instantiate.patch
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