From: Benjamin Coddington <bcodding@redhat.com>
Date: Fri, 20 Nov 2015 14:56:20 +0000 (-0500)
Subject: nfs4: start callback_ident at idr 1
X-Git-Tag: v4.1.12-92~201^2~18
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=429ef663c1ec2f81487a760dd9e12b764deb1d0a;p=users%2Fjedix%2Flinux-maple.git

nfs4: start callback_ident at idr 1

Orabug: 22623874

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>

(cherry picked from commit 254cbeb139be712a9dbcfcaea997a3e3dfd9be52)
Signed-off-by: Dan Duval <dan.duval@oracle.com>
---

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index e42be52a8c18d..5dea913baf46c 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -33,7 +33,7 @@ static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
 		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);