From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH] bnx2x: fix panic when TX ring is full Date: Wed, 13 Jun 2012 21:45:16 +0200 Message-ID: <1339616716.22704.661.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev , Tom Herbert , Robert Evans , Eilon Greenstein , Merav Sicron , Yaniv Rosner , Willem de Bruijn , Tomas Hruby To: David Miller Return-path: Received: from mail-ey0-f174.google.com ([209.85.215.174]:54210 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754212Ab2FMTpV (ORCPT ); Wed, 13 Jun 2012 15:45:21 -0400 Received: by eaak11 with SMTP id k11so333585eaa.19 for ; Wed, 13 Jun 2012 12:45:20 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet 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 --- drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c index ad0743b..302765a 100644 --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c @@ -190,7 +190,7 @@ int bnx2x_tx_int(struct bnx2x *bp, struct bnx2x_fp_txdata *txdata) 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); @@ -2501,8 +2501,6 @@ int bnx2x_poll(struct napi_struct *napi, int budget) /* 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, @@ -3156,7 +3154,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev) 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 @@ -3165,7 +3163,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev) 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++;