From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH net-next v2 2/4] ipv6: enable IPV6_FLOWLABEL_MGR for getsockopt Date: Tue, 5 Nov 2013 17:08:38 +0100 Message-ID: <20131105160838.GH8832@order.stressinduktion.org> References: <1383661738-6083-1-git-send-email-florent.fourcot@enst-bretagne.fr> <1383661738-6083-2-git-send-email-florent.fourcot@enst-bretagne.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: netdev@vger.kernel.org To: Florent Fourcot Return-path: Received: from order.stressinduktion.org ([87.106.68.36]:51045 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751263Ab3KEQIj (ORCPT ); Tue, 5 Nov 2013 11:08:39 -0500 Content-Disposition: inline In-Reply-To: <1383661738-6083-2-git-send-email-florent.fourcot@enst-bretagne.fr> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Nov 05, 2013 at 03:28:56PM +0100, Florent Fourcot wrote: > + spin_lock_bh(&ip6_fl_lock); > + rcu_read_lock_bh(); > + > + for_each_sk_fl_rcu(np, sfl) { > + if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) { The iteration is protected by rcu, so need to take the ip6_fl_lock. We should lock the smallest region which needs to be protected. This is only the body of the if. Using fl->label without lock is fine, because it is immutable after interning. > + freq->flr_label = sfl->fl->label; > + freq->flr_dst = sfl->fl->dst; > + freq->flr_share = sfl->fl->share; > + freq->flr_expires = (sfl->fl->expires - jiffies) / HZ; > + freq->flr_linger = sfl->fl->linger / HZ; > + > + rcu_read_unlock_bh(); > + spin_unlock_bh(&ip6_fl_lock); Please reverse these two lines then. Could you take a look at your patch regarding fl6_renew, too? Can we push locking into the function there, too? Greetings, Hannes