summaryrefslogtreecommitdiff
path: root/net/ipv4/tcp_input.c
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2012-07-30 03:20:37 +0400
committerDavid S. Miller <davem@davemloft.net>2012-07-31 01:53:22 +0400
commit404e0a8b6a55d5e1cd138c6deb1bca9abdf75d8c (patch)
tree38e9748d38c415cc97b973fecb9279cd43f76393 /net/ipv4/tcp_input.c
parentcca32e4bf999a34ac08d959f351f2b30bcd02460 (diff)
downloadlinux-404e0a8b6a55d5e1cd138c6deb1bca9abdf75d8c.tar.xz
net: ipv4: fix RCU races on dst refcounts
commit c6cffba4ffa2 (ipv4: Fix input route performance regression.) added various fatal races with dst refcounts. crashes happen on tcp workloads if routes are added/deleted at the same time. The dst_free() calls from free_fib_info_rcu() are clearly racy. We need instead regular dst refcounting (dst_release()) and make sure dst_release() is aware of RCU grace periods : Add DST_RCU_FREE flag so that dst_release() respects an RCU grace period before dst destruction for cached dst Introduce a new inet_sk_rx_dst_set() helper, using atomic_inc_not_zero() to make sure we dont increase a zero refcount (On a dst currently waiting an rcu grace period before destruction) rt_cache_route() must take a reference on the new cached route, and release it if was not able to install it. With this patch, my machines survive various benchmarks. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a356e1fecf9a..9be30b039ae3 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5604,8 +5604,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
tcp_set_state(sk, TCP_ESTABLISHED);
if (skb != NULL) {
- sk->sk_rx_dst = dst_clone(skb_dst(skb));
- inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
+ inet_sk_rx_dst_set(sk, skb);
security_inet_conn_established(sk, skb);
}