From 8fd222ebb4be73c7478d44d4b415b634a1841f8b Mon Sep 17 00:00:00 2001
From: Matt Macy <mmacy@FreeBSD.org>
Date: Fri, 4 May 2018 18:59:01 +0000
Subject: [PATCH] fix case where pidx_last might be used uninitialized

Reviewed by:	sbruno
---
 sys/dev/e1000/em_txrx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/e1000/em_txrx.c b/sys/dev/e1000/em_txrx.c
index 5344496a55f..a1f51ba6958 100644
--- a/sys/dev/e1000/em_txrx.c
+++ b/sys/dev/e1000/em_txrx.c
@@ -401,7 +401,7 @@ em_isc_txd_encap(void *arg, if_pkt_info_t pi)
 	 * needs End Of Packet (EOP)
 	 * and Report Status (RS)
 	 */
-	if (txd_flags) {
+	if (txd_flags && nsegs) {
 		txr->tx_rsq[txr->tx_rs_pidx] = pidx_last;
 		DPRINTF(iflib_get_dev(sc->ctx), "setting to RS on %d rs_pidx %d first: %d\n", pidx_last, txr->tx_rs_pidx, first);
 		txr->tx_rs_pidx = (txr->tx_rs_pidx+1) & (ntxd-1);