NFS: Ignore connections that have cl_rpcclient uninitialized

cl_rpcclient starts as ERR_PTR(-EINVAL), and connections like that
are floating freely through the system.  Most places check whether
pointer is valid before dereferencing it, but newly added code
in nfs_match_client does not.

Which causes crashes when more than one NFS mount point is present.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 7555ba889d1fce916cc96b8f23c03ad4d6037366..ebecfb8fba067cd4316e1c59e12c472c97d930a6 100644 (file)
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -314,7 +314,8 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
                /* Match the full socket address */
                if (!rpc_cmp_addr_port(sap, clap))
                        /* Match all xprt_switch full socket addresses */
-                       if (!rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
+                       if (IS_ERR(clp->cl_rpcclient) ||
+                            !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
                                                           sap))
                                continue;