From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: [PATCH net 1/3] net: bcmgenet: fix off-by-one in incrementing read pointer Date: Thu, 9 Oct 2014 18:06:35 -0700 Message-ID: <1412903197-19193-2-git-send-email-f.fainelli@gmail.com> References: <1412903197-19193-1-git-send-email-f.fainelli@gmail.com> Cc: davem@davemloft.net, pgynther@google.com, jaedon.shin@gmail.com, Florian Fainelli To: netdev@vger.kernel.org Return-path: Received: from mail-pa0-f45.google.com ([209.85.220.45]:57567 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212AbaJJBGz (ORCPT ); Thu, 9 Oct 2014 21:06:55 -0400 Received: by mail-pa0-f45.google.com with SMTP id rd3so696947pab.4 for ; Thu, 09 Oct 2014 18:06:54 -0700 (PDT) In-Reply-To: <1412903197-19193-1-git-send-email-f.fainelli@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Commit b629be5c8399d7c423b92135eb43a86c924d1cbc ("net: bcmgenet: check harder for out of memory conditions") moved the increment of the local read pointer *before* reading from the hardware descriptor using dmadesc_get_length_status(), which creates an off-by-one situation. Fix this by moving again the read_ptr increment after we have read the hardware descriptor to get both the control block and the read pointer back in sync. Fixes: b629be5c8399 ("net: bcmgenet: check harder for out of memory conditions") Reported-by: Jaedon Shin Signed-off-by: Florian Fainelli --- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index fff2634b6f34..f1bcebcbba80 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -1287,9 +1287,6 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv, rxpktprocessed++; - priv->rx_read_ptr++; - priv->rx_read_ptr &= (priv->num_rx_bds - 1); - /* We do not have a backing SKB, so we do not have a * corresponding DMA mapping for this incoming packet since * bcmgenet_rx_refill always either has both skb and mapping or @@ -1332,6 +1329,9 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv, __func__, p_index, priv->rx_c_index, priv->rx_read_ptr, dma_length_status); + priv->rx_read_ptr++; + priv->rx_read_ptr &= (priv->num_rx_bds - 1); + if (unlikely(!(dma_flag & DMA_EOP) || !(dma_flag & DMA_SOP))) { netif_err(priv, rx_status, dev, "dropping fragmented packet!\n"); -- 1.9.1