[PATCH 3.8 36/91] ipv6: fix possible seqlock deadlock in ip6_finish_output2

[Kamal Mostafa]

3.8.13.15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ 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 <eric.dumazet@xxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 net/ipv6/ip6_output.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index ac9f072..09cf37e 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -128,8 +128,8 @@ static int ip6_finish_output2(struct sk_buff *skb)
 	if (neigh)
 		return dst_neigh_output(dst, neigh, skb);
 
-	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;
 }
-- 
1.8.3.2

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