From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wei Subject: [PATCH] IPv6: Fix Smatch warning. Date: Thu, 08 Mar 2012 08:58:07 +0800 Message-ID: <4F58041F.5060209@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Dan Carpenter , netdev To: "David S. Miller" Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:42163 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751485Ab2CHBNY (ORCPT ); Wed, 7 Mar 2012 20:13:24 -0500 Sender: netdev-owner@vger.kernel.org List-ID: With commit d6ddef9e641d(IPv6: Fix not join all-router mcast group when forwarding set.) I check 'dev' after it's dereference that leads to a Smatch complaint: net/ipv6/addrconf.c:438 ipv6_add_dev() warn: variable dereferenced before check 'dev' (see line 432) net/ipv6/addrconf.c 431 /* protected by rtnl_lock */ 432 rcu_assign_pointer(dev->ip6_ptr, ndev); ^^^^^^^^^^^^ Old dereference. 433 434 /* Join all-node multicast group */ 435 ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes); 436 437 /* Join all-router multicast group if forwarding is set */ 438 if (ndev->cnf.forwarding && dev && (dev->flags & IFF_MULTICAST)) ^^^ Remove the check to avoid the complaint as 'dev' can't be NULL. Reported-by: Dan Carpenter Signed-off-by: Li Wei --- net/ipv6/addrconf.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 6b8ebc5..6a3bb60 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -435,7 +435,7 @@ static struct inet6_dev * ipv6_add_dev(struct net_device *dev) ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes); /* Join all-router multicast group if forwarding is set */ - if (ndev->cnf.forwarding && dev && (dev->flags & IFF_MULTICAST)) + if (ndev->cnf.forwarding && (dev->flags & IFF_MULTICAST)) ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters); return ndev; -- 1.7.1