From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753443AbaHSScG (ORCPT ); Tue, 19 Aug 2014 14:32:06 -0400 Received: from mail-ig0-f176.google.com ([209.85.213.176]:39742 "EHLO mail-ig0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751576AbaHSScF (ORCPT ); Tue, 19 Aug 2014 14:32:05 -0400 Message-ID: <1408473119.5604.4.camel@edumazet-glaptop2.roam.corp.google.com> Subject: Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy() From: Eric Dumazet To: Jonas Jensen Cc: netdev@vger.kernel.org, davem@davemloft.net, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, f.fainelli@gmail.com, bhutchings@solarflare.com Date: Tue, 19 Aug 2014 11:31:59 -0700 In-Reply-To: <1408459784-9385-2-git-send-email-jonas.jensen@gmail.com> References: <1408459784-9385-1-git-send-email-jonas.jensen@gmail.com> <1408459784-9385-2-git-send-email-jonas.jensen@gmail.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-08-19 at 16:49 +0200, Jonas Jensen wrote: > build_skb() is used to make skbs out of existing RX ring memory > which is bad because the RX ring is allocated only once, on probe. > Memory corruption occur because said memory is reclaimed, i.e. > __kfree_skb() (and eventually put_page()). > > Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy(). > Also, synchronize DMA memory before passing skb to napi_gro_receive(). > > Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041 Wow, this driver was really buggy. Patch is not complete. Instead of : priv->rx_buf_size = RX_BUF_SIZE + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); I think rx_buf_size can now be RX_BUF_SIZE Another point is that priv->stats seems not needed, as ndev->stats could be used instead (and remove moxart_mac_get_stats()) From mboxrd@z Thu Jan 1 00:00:00 1970 From: eric.dumazet@gmail.com (Eric Dumazet) Date: Tue, 19 Aug 2014 11:31:59 -0700 Subject: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy() In-Reply-To: <1408459784-9385-2-git-send-email-jonas.jensen@gmail.com> References: <1408459784-9385-1-git-send-email-jonas.jensen@gmail.com> <1408459784-9385-2-git-send-email-jonas.jensen@gmail.com> Message-ID: <1408473119.5604.4.camel@edumazet-glaptop2.roam.corp.google.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2014-08-19 at 16:49 +0200, Jonas Jensen wrote: > build_skb() is used to make skbs out of existing RX ring memory > which is bad because the RX ring is allocated only once, on probe. > Memory corruption occur because said memory is reclaimed, i.e. > __kfree_skb() (and eventually put_page()). > > Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy(). > Also, synchronize DMA memory before passing skb to napi_gro_receive(). > > Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041 Wow, this driver was really buggy. Patch is not complete. Instead of : priv->rx_buf_size = RX_BUF_SIZE + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); I think rx_buf_size can now be RX_BUF_SIZE Another point is that priv->stats seems not needed, as ndev->stats could be used instead (and remove moxart_mac_get_stats())