From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Fri, 29 Nov 2013 05:39:44 +0000 (+0100)
Subject: ipv6: fix possible seqlock deadlock in ip6_finish_output2
X-Git-Tag: v3.13-rc3~28^2~11
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=7f88c6b23afbd31545c676dea77ba9593a1a14bf;p=linux.git

ipv6: fix possible seqlock deadlock in ip6_finish_output2

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 <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 59df872e2f4d..4acdb63495db 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -116,8 +116,8 @@ static int ip6_finish_output2(struct sk_buff *skb)
 	}
 	rcu_read_unlock_bh();
 
-	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;
 }