| From 79fec1e3bb0db644023e3e7ff938c523bb143938 Mon Sep 17 00:00:00 2001 |
| From: Hannes Frederic Sowa <hannes@stressinduktion.org> |
| Date: Fri, 29 Nov 2013 06:39:44 +0100 |
| Subject: ipv6: fix possible seqlock deadlock in ip6_finish_output2 |
| |
| From: Hannes Frederic Sowa <hannes@stressinduktion.org> |
| |
| [ 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@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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| 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 |
| @@ -141,8 +141,8 @@ static int ip6_finish_output2(struct sk_ |
| } |
| 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; |
| } |
