From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162959Ab2GLXm3 (ORCPT ); Thu, 12 Jul 2012 19:42:29 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:44509 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759589Ab2GLWiM (ORCPT ); Thu, 12 Jul 2012 18:38:12 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Tomas Hruby , Eric Dumazet , Eilon Greenstein , Yaniv Rosner , Merav Sicron , Tom Herbert , Robert Evans , Willem de Bruijn , "David S. Miller" Subject: [ 038/187] bnx2x: fix panic when TX ring is full Date: Thu, 12 Jul 2012 15:33:14 -0700 Message-Id: <20120712191525.861189826@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit bc14786a100cc6a81cd060e8031ec481241b418c ] There is a off by one error in the minimal number of BD in bnx2x_start_xmit() and bnx2x_tx_int() before stopping/resuming tx queue. A full size GSO packet, with data included in skb->head really needs (MAX_SKB_FRAGS + 4) BDs, because of bnx2x_tx_split() This error triggers if BQL is disabled and heavy TCP transmit traffic occurs. bnx2x_tx_split() definitely can be called, remove a wrong comment. Reported-by: Tomas Hruby Signed-off-by: Eric Dumazet Cc: Eilon Greenstein Cc: Yaniv Rosner Cc: Merav Sicron Cc: Tom Herbert Cc: Robert Evans Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c @@ -191,7 +191,7 @@ int bnx2x_tx_int(struct bnx2x *bp, struc if ((netif_tx_queue_stopped(txq)) && (bp->state == BNX2X_STATE_OPEN) && - (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 3)) + (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 4)) netif_tx_wake_queue(txq); __netif_tx_unlock(txq); @@ -2349,8 +2349,6 @@ int bnx2x_poll(struct napi_struct *napi, /* we split the first BD into headers and data BDs * to ease the pain of our fellow microcode engineers * we use one mapping for both BDs - * So far this has only been observed to happen - * in Other Operating Systems(TM) */ static noinline u16 bnx2x_tx_split(struct bnx2x *bp, struct bnx2x_fp_txdata *txdata, @@ -3002,7 +3000,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_b txdata->tx_bd_prod += nbd; - if (unlikely(bnx2x_tx_avail(bp, txdata) < MAX_SKB_FRAGS + 3)) { + if (unlikely(bnx2x_tx_avail(bp, txdata) < MAX_SKB_FRAGS + 4)) { netif_tx_stop_queue(txq); /* paired memory barrier is in bnx2x_tx_int(), we have to keep @@ -3011,7 +3009,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_b smp_mb(); fp->eth_q_stats.driver_xoff++; - if (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 3) + if (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 4) netif_tx_wake_queue(txq); } txdata->tx_pkt++;