Index: nfs_vfsops.c
===================================================================
--- nfs_vfsops.c	(revision 180682)
+++ nfs_vfsops.c	(working copy)
@@ -105,7 +105,7 @@
         downdelayinterval, CTLFLAG_RW, &nfs_tprintf_delay, 0, "");
 
 static void	nfs_decode_args(struct mount *mp, struct nfsmount *nmp,
-		    struct nfs_args *argp);
+		    struct nfs_args *argp, char *hst);
 static int	mountnfs(struct nfs_args *, struct mount *,
 		    struct sockaddr *, char *, struct vnode **,
 		    struct ucred *cred);
@@ -538,7 +538,8 @@
 }
 
 static void
-nfs_decode_args(struct mount *mp, struct nfsmount *nmp, struct nfs_args *argp)
+nfs_decode_args(struct mount *mp, struct nfsmount *nmp, struct nfs_args *argp,
+    char *hst)
 {
 	int s;
 	int adjsock;
@@ -704,7 +705,7 @@
 			}
 	}
 
-	strlcpy(nmp->nm_hostname, argp->hostname, sizeof(nmp->nm_hostname));
+	strlcpy(nmp->nm_hostname, hst, sizeof(nmp->nm_hostname));
 	p = strchr(nmp->nm_hostname, ':');
 	if (p)
 		*p = '\0';
@@ -797,7 +798,12 @@
 		    ~(NFSMNT_NFSV3 | NFSMNT_NOLOCKD /*|NFSMNT_XLATECOOKIE*/)) |
 		    (nmp->nm_flag &
 			(NFSMNT_NFSV3 | NFSMNT_NOLOCKD /*|NFSMNT_XLATECOOKIE*/));
-		nfs_decode_args(mp, nmp, &args);
+		error = copyinstr(args.hostname, hst, MNAMELEN-1, &len);
+		if (error)
+			goto out;
+		bzero(&hst[len], MNAMELEN - len);
+		nfs_decode_args(mp, nmp, &args, hst);
+
 		goto out;
 	}
 
@@ -935,7 +941,7 @@
 	nmp->nm_soproto = argp->proto;
 	nmp->nm_rpcops = &nfs_rpcops;
 
-	nfs_decode_args(mp, nmp, argp);
+	nfs_decode_args(mp, nmp, argp, hst);
 
 	/*
 	 * For Connection based sockets (TCP,...) defer the connect until