From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: virt-manager broken by bind(0) in net-next. Date: Sat, 31 Jan 2009 00:50:08 +0300 Message-ID: <20090130215008.GB12210@ioremap.net> References: <20090130112125.GA9908@ioremap.net> <20090130125337.GA7155@gondor.apana.org.au> <20090130095737.103edbff@extreme> <498349F7.4050300@cosmosbay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stephen Hemminger , Herbert Xu , berrange@redhat.com, et-mgmt-tools@redhat.com, davem@davemloft.net, netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from netgear.net.ru ([195.178.208.66]:48499 "EHLO tservice.net.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752898AbZA3VuL (ORCPT ); Fri, 30 Jan 2009 16:50:11 -0500 Content-Disposition: inline In-Reply-To: <498349F7.4050300@cosmosbay.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Jan 30, 2009 at 07:41:59PM +0100, Eric Dumazet (dada1@cosmosbay.com) wrote: > Reviewing commit a9d8f9110d7e953c2f2b521087a4179677843c2a > > I see use of a hashinfo->bsockets field that : > > - lacks proper lock/synchronization It should contain rough number of sockets, there is no need to be very precise because of this hueristic. > - suffers from cache line ping pongs on SMP I used free alignment slot so that socket structure would not be icreased. > Also there might be a problem at line 175 > > if (sk->sk_reuse && sk->sk_state != TCP_LISTEN && --attempts >= 0) { > spin_unlock(&head->lock); > goto again; > > If we entered inet_csk_get_port() with a non null snum, we can "goto again" > while it was not expected. > > diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c > index df8e72f..752c6b2 100644 > --- a/net/ipv4/inet_connection_sock.c > +++ b/net/ipv4/inet_connection_sock.c > @@ -172,7 +172,8 @@ tb_found: > } else { > ret = 1; > if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) { > - if (sk->sk_reuse && sk->sk_state != TCP_LISTEN && --attempts >= 0) { > + if (sk->sk_reuse && sk->sk_state != TCP_LISTEN && > + smallest_size == -1 && --attempts >= 0) { I think it should be smallest_size != -1, since we really want to goto to the again label when hueristic is used, which in turn changes smallest_size. -- Evgeniy Polyakov