On Fri, Jun 07, 2013 at 07:11:57AM +0100, Ben Hutchings wrote: > On Tue, 2013-06-04 at 19:24 +0200, Willy Tarreau wrote: > > 2.6.32-longterm review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Eric Dumazet <eric.dumazet@xxxxxxxxx> > > > > commit f6d8bd051c391c1c0458a30b2a7abcd939329259 upstream. > > > > 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 <eric.dumazet@xxxxxxxxx> > > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > > [dannf/bwh: backported to Debian's 2.6.32] > > Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> added, thank you. willy -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html