Another fix that wasn't pulled in from the MAC branch: the

struct mount is not cached as *mp at this point, so use
vp->v_mount directly, following the check that it's non-NULL.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs

sys/compat/linux/linux_stats.c

@@ -360,7 +360,8 @@ linux_ustat(struct thread *td, struct linux_ustat_args *args)
 		if (vp->v_mount == NULL)
 			return (EINVAL);
 #ifdef MAC
-		error = mac_check_mount_stat(td->td_proc->p_ucred, mp);
+		error = mac_check_mount_stat(td->td_proc->p_ucred,
+		    vp->v_mount);
 		if (error)
 			return (error);
 #endif