From f6d8bd051c391c1c0458a30b2a7abcd939329259 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 21 Apr 2011 09:45:37 +0000 Subject: inet: add RCU protection to inet->opt We lack proper synchronization to manipulate inet->opt ip_options Problem is ip_make_skb() calls ip_setup_cork() and ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options), without any protection against another thread manipulating inet->opt. Another thread can change inet->opt pointer and free old one under us. Use RCU to protect inet->opt (changed to inet->inet_opt). Instead of handling atomic refcounts, just copy ip_options when necessary, to avoid cache line dirtying. We cant insert an rcu_head in struct ip_options since its included in skb->cb[], so this patch is large because I had to introduce a new ip_options_rcu structure. Signed-off-by: Eric Dumazet Cc: Herbert Xu Signed-off-by: David S. Miller --- net/dccp/ipv6.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/dccp/ipv6.c') diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 73add2373247..8dc4348774a5 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -573,7 +573,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk, First: no IPv4 options. */ - newinet->opt = NULL; + newinet->inet_opt = NULL; /* Clone RX bits */ newnp->rxopt.all = np->rxopt.all; -- cgit v1.2.3