Patch "nfs4: start callback_ident at idr 1" has been added to the 4.2-stable tree

Patch "nfs4: start callback_ident at idr 1" has been added to the 4.2-stable tree

[gregkh]

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

    nfs4: start callback_ident at idr 1

to the 4.2-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:
     nfs4-start-callback_ident-at-idr-1.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c68a027c05709330fe5b2f50c50d5fa02124b5d8 Mon Sep 17 00:00:00 2001
From: Benjamin Coddington <bcodding@redhat.com>
Date: Fri, 20 Nov 2015 09:56:20 -0500
Subject: nfs4: start callback_ident at idr 1

From: Benjamin Coddington <bcodding@redhat.com>

commit c68a027c05709330fe5b2f50c50d5fa02124b5d8 upstream.

If clp->cl_cb_ident is zero, then nfs_cb_idr_remove_locked() skips removing
it when the nfs_client is freed.  A decoding or server bug can then find
and try to put that first nfs_client which would lead to a crash.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: d6870312659d ("nfs4client: convert to idr_alloc()")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/nfs4client.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -33,7 +33,7 @@ static int nfs_get_cb_ident_idr(struct n
 		return ret;
 	idr_preload(GFP_KERNEL);
 	spin_lock(&nn->nfs_client_lock);
-	ret = idr_alloc(&nn->cb_ident_idr, clp, 0, 0, GFP_NOWAIT);
+	ret = idr_alloc(&nn->cb_ident_idr, clp, 1, 0, GFP_NOWAIT);
 	if (ret >= 0)
 		clp->cl_cb_ident = ret;
 	spin_unlock(&nn->nfs_client_lock);


Patches currently in stable-queue which might be from bcodding@redhat.com are

queue-4.2/nfs4-start-callback_ident-at-idr-1.patch
queue-4.2/nfs4-limit-callback-decoding-to-received-bytes.patch