From: weidong <[EMAIL PROTECTED]> Date: Wed, 14 Feb 2007 11:30:57 -0500
> when I use linux TCP socket, and find there is a bug in function > sk_acceptq_is_full(). ... > Consider an example: > > After listen(sockfd, 1) system call, sk->sk_max_ack_backlog is set to > 1. As we know, sk->sk_ack_backlog is initialized to 0. Assuming accept() > system call is not invoked now. > > 1. 1st connection comes. invoke sk_acceptq_is_full(). sk- > >sk_ack_backlog=0 sk->sk_max_ack_backlog=1, function return 0 accept > this connection. Increase the sk->sk_ack_backlog > 2. 2nd connection comes. invoke sk_acceptq_is_full(). sk- > >sk_ack_backlog=1 sk->sk_max_ack_backlog=1, function return 0 accept > this connection. Increase the sk->sk_ack_backlog > 3. 3rd connection comes. invoke sk_acceptq_is_full(). sk- > >sk_ack_backlog=2 sk->sk_max_ack_backlog=1, function return 1. Refuse > this connection. > > I think it has bugs. after listen system call. sk->sk_max_ack_backlog=1 > but now it can accept 2 connections. The following patch can fix this > problem. > > signed-off-by: Wei Dong <[EMAIL PROTECTED]> Thank you very much for the detailed analysis and fix. Actually, this bug exists all over the tree I believe, not just in TCP. I would like to audit all uses of sk_ack_backlog and sk_max_ack_backlog before applying your patch, so please give me some time to perform a quick audit. Thank you. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
