From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Hannes Frederic Sowa , Eric Dumazet , "David S. Miller" Subject: [PATCH 3.4 23/32] ipv6: fix possible seqlock deadlock in ip6_finish_output2 Date: Fri, 6 Dec 2013 13:52:33 -0800 Message-Id: <20131206214958.951566945@linuxfoundation.org> In-Reply-To: <20131206214956.830407026@linuxfoundation.org> References: <20131206214956.830407026@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Frederic Sowa [ Upstream commit 7f88c6b23afbd31545c676dea77ba9593a1a14bf ] IPv6 stats are 64 bits and thus are protected with a seqlock. By not disabling bottom-half we could deadlock here if we don't disable bh and a softirq reentrantly updates the same mib. Cc: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -144,8 +144,8 @@ static int ip6_finish_output2(struct sk_ return res; } rcu_read_unlock(); - IP6_INC_STATS_BH(dev_net(dst->dev), - ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); + IP6_INC_STATS(dev_net(dst->dev), + ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); kfree_skb(skb); return -EINVAL; }