diff -ur sys/dev/em/if_em.c /usr/src/sys/dev/em/if_em.c
--- sys/dev/em/if_em.c	Sat Apr  8 12:21:31 2006
+++ /usr/src/sys/dev/em/if_em.c	Mon Apr 10 14:58:54 2006
@@ -3083,7 +3083,9 @@
 			i = 0;
 		if (m != NULL) {
 			sc->next_rx_desc_to_check = i;
+			EM_UNLOCK(sc);
 			(*ifp->if_input)(ifp, m);
+			EM_LOCK(sc);
 			i = sc->next_rx_desc_to_check;
 		}
 		current_desc = &sc->rx_desc_base[i];