--- sys/compat/linux/linux_futex.c	2008-11-22 14:40:19.000000000 +0800
+++ /var/current/mysrc/sys/compat/linux/linux_futex.c	2008-11-24 12:55:12.000000000 +0800
@@ -551,6 +551,8 @@
 		return (EINVAL);
 
 	em = em_find(td->td_proc, EMUL_DOLOCK);
+
+	KASSERT(em != NULL, ("linux_set_robust_list: emuldata not found.\n"));
 	em->robust_futexes = args->head;
 	EMUL_UNLOCK(&emul_lock);