From patchwork Wed Mar 27 20:35:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaro Koskinen X-Patchwork-Id: 1067402 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=iki.fi Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44V0C40xlMz9sPn for ; Thu, 28 Mar 2019 07:36:16 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727952AbfC0UgM (ORCPT ); Wed, 27 Mar 2019 16:36:12 -0400 Received: from emh06.mail.saunalahti.fi ([62.142.5.116]:55304 "EHLO emh06.mail.saunalahti.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726108AbfC0Ufx (ORCPT ); Wed, 27 Mar 2019 16:35:53 -0400 Received: from localhost.localdomain (85-76-9-223-nat.elisa-mobile.fi [85.76.9.223]) by emh06.mail.saunalahti.fi (Postfix) with ESMTP id 614F93009A; Wed, 27 Mar 2019 22:35:51 +0200 (EET) From: Aaro Koskinen To: "David S. Miller" , Jose Abreu , Alexandre Torgue , Giuseppe Cavallaro , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Aaro Koskinen Subject: [PATCH 5/6] net: stmmac: fix dropping of multi-descriptor RX frames Date: Wed, 27 Mar 2019 22:35:39 +0200 Message-Id: <20190327203540.1884-6-aaro.koskinen@iki.fi> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20190327203540.1884-1-aaro.koskinen@iki.fi> References: <20190327203540.1884-1-aaro.koskinen@iki.fi> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Aaro Koskinen Packets without the last descriptor set should be dropped early. If we receive a frame larger than the DMA buffer, the HW will continue using the next descriptor. Driver mistakes these as individual frames, and sometimes a truncated frame (without the LD set) may look like a valid packet. This fixes a strange issue where the system replies to 4098-byte ping although the MTU/DMA buffer size is set to 4096, and yet at the same time it's logging an oversized packet. Signed-off-by: Aaro Koskinen --- drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c index c42ef6c729c0..5202d6ad7919 100644 --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c @@ -201,6 +201,11 @@ static int enh_desc_get_rx_status(void *data, struct stmmac_extra_stats *x, if (unlikely(rdes0 & RDES0_OWN)) return dma_own; + if (unlikely(!(rdes0 & RDES0_LAST_DESCRIPTOR))) { + stats->rx_length_errors++; + return discard_frame; + } + if (unlikely(rdes0 & RDES0_ERROR_SUMMARY)) { if (unlikely(rdes0 & RDES0_DESCRIPTOR_ERROR)) { x->rx_desc++;