From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerhard Stenzel Subject: Re: [PATCH net] vxlan: fix incorrect initializer in union vxlan_addr Date: Tue, 19 Aug 2014 22:36:43 +0200 Message-ID: <53F3B55B.6070505@linux.vnet.ibm.com> References: <53EDCC19.70702@linux.vnet.ibm.com> <53EDCCFE.5090301@linux.vnet.ibm.com> <20140818.101143.2274310300741627370.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from e06smtp16.uk.ibm.com ([195.75.94.112]:32807 "EHLO e06smtp16.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916AbaHSUgs (ORCPT ); Tue, 19 Aug 2014 16:36:48 -0400 Received: from /spool/local by e06smtp16.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 19 Aug 2014 21:36:47 +0100 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 28C6E17D8045 for ; Tue, 19 Aug 2014 21:38:36 +0100 (BST) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s7JKaiLd35651608 for ; Tue, 19 Aug 2014 20:36:44 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s7JKahfI004628 for ; Tue, 19 Aug 2014 14:36:44 -0600 In-Reply-To: <20140818.101143.2274310300741627370.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: Trying again ... On 08/18/2014 07:11 PM, David Miller wrote: ... > > Your patch was corrupted by your email client, also please do not > indent your signoff. > > THanks. > The first initializer in the following union vxlan_addr ipa = { .sin.sin_addr.s_addr = tip, .sa.sa_family = AF_INET, }; is optimised away by the compiler, due to the second initializer, therefore initialising .sin.sin_addr.s_addr always to 0. This results in netlink messages indicating a L3 miss never contain the missed IP address. This was observed with GCC 4.8 and 4.9. I do not know about previous versions. The problem affects user space programs relying on an IP address being sent as part of a netlink message indicating a L3 miss. Changing .sa.sa_family = AF_INET, to .sin.sin_family = AF_INET, fixes the problem. Signed-off-by: Gerhard Stenzel --- diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 1fb7b37..beb377b 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -1327,7 +1327,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb) } else if (vxlan->flags & VXLAN_F_L3MISS) { union vxlan_addr ipa = { .sin.sin_addr.s_addr = tip, - .sa.sa_family = AF_INET, + .sin.sin_family = AF_INET, }; vxlan_ip_miss(dev, &ipa); @@ -1488,7 +1488,7 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb) } else if (vxlan->flags & VXLAN_F_L3MISS) { union vxlan_addr ipa = { .sin6.sin6_addr = msg->target, - .sa.sa_family = AF_INET6, + .sin6.sin6_family = AF_INET6, }; vxlan_ip_miss(dev, &ipa); @@ -1521,7 +1521,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) if (!n && (vxlan->flags & VXLAN_F_L3MISS)) { union vxlan_addr ipa = { .sin.sin_addr.s_addr = pip->daddr, - .sa.sa_family = AF_INET, + .sin.sin_family = AF_INET, }; vxlan_ip_miss(dev, &ipa); @@ -1542,7 +1542,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) if (!n && (vxlan->flags & VXLAN_F_L3MISS)) { union vxlan_addr ipa = { .sin6.sin6_addr = pip6->daddr, - .sa.sa_family = AF_INET6, + .sin6.sin6_family = AF_INET6, }; vxlan_ip_miss(dev, &ipa);