From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754632Ab2GIOlV (ORCPT ); Mon, 9 Jul 2012 10:41:21 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38288 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754493Ab2GIOiX (ORCPT ); Mon, 9 Jul 2012 10:38:23 -0400 Message-Id: <20120709143122.140128311@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 09 Jul 2012 15:31:54 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Dumazet , Bogdan Hamciuc , Herbert Xu , Neil Horman , Cong Wang , "David S. Miller" Subject: [ 38/48] netpoll: fix netpoll_send_udp() bugs In-Reply-To: <20120709143116.348975190@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 954fba0274058d27c7c07b5ea07c41b3b7477894 ] Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() : "skb->len += len;" instead of "skb_put(skb, len);" Meaning that _if_ a network driver needs to call skb_realloc_headroom(), only packet headers would be copied, leaving garbage in the payload. However the skb_realloc_headroom() must be avoided as much as possible since it requires memory and netpoll tries hard to work even if memory is exhausted (using a pool of preallocated skbs) It appears netpoll_send_udp() reserved 16 bytes for the ethernet header, which happens to work for typicall drivers but not all. Right thing is to use LL_RESERVED_SPACE(dev) (And also add dev->needed_tailroom of tailroom) This patch combines both fixes. Many thanks to Bogdan for raising this issue. Reported-by: Bogdan Hamciuc Signed-off-by: Eric Dumazet Tested-by: Bogdan Hamciuc Cc: Herbert Xu Cc: Neil Horman Reviewed-by: Neil Horman Reviewed-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/core/netpoll.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index ab0633f..db4bb7a 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -351,22 +351,23 @@ EXPORT_SYMBOL(netpoll_send_skb_on_dev); void netpoll_send_udp(struct netpoll *np, const char *msg, int len) { - int total_len, eth_len, ip_len, udp_len; + int total_len, ip_len, udp_len; struct sk_buff *skb; struct udphdr *udph; struct iphdr *iph; struct ethhdr *eth; udp_len = len + sizeof(*udph); - ip_len = eth_len = udp_len + sizeof(*iph); - total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; + ip_len = udp_len + sizeof(*iph); + total_len = ip_len + LL_RESERVED_SPACE(np->dev); - skb = find_skb(np, total_len, total_len - len); + skb = find_skb(np, total_len + np->dev->needed_tailroom, + total_len - len); if (!skb) return; skb_copy_to_linear_data(skb, msg, len); - skb->len += len; + skb_put(skb, len); skb_push(skb, sizeof(*udph)); skb_reset_transport_header(skb);